Clarification on Arcane Trickster multiclassing into Wizard

[Kyou]

Hey, I'm preparing for a new campaign my group starts tomorrow. I thought I'd try Arcane Trickster with some Wizard levels. I found a guide from this site. Can't post links yet but it's called Magique Filou: The Arcane Trickster's Guide

And the following build seemed good so I thought I'd try it with some changes:
THE RINGLEADER
Feral Tiefling Arcane Trickster 11/Diviner Wizard 9
ST8, DX20, CO16, IN18, WI12, CH10
ASI’s: DEX+4, IN+1 CO+1, IN+2, Resilient (CON)
Expertise: Arcana, Investigation, Insight, Stealth
Cantrips: Mage Hand, Booming Blade, Minor Illusion, Friends, Message, Mending, Toll the Dead, Fire Bolt
Spells: 1 – Charm Person, Tasha’s Hideous Laughter, Disguise Self, Find Familiar; 2 – Invisibility, Mirror Image, Hold Person, Blindness; 3 – Hypnotic Pattern, Major Image, Counterspell; 4 – Greater Invisibility, Evard’s Black Tentacles
(Wizard) 1 – Absorb Elements, Alarm, Shield; 2 – Alter Self, Levitate, Mind Spike; 3 – Clairvoyance, Fireball, Fly; 4 – Banishment, Fire Shield; 5 – Dominate Person, Scrying

I'm mainly confused about multiclassing and spells. In the list above, I see character of level 20 with lvl11 AT and lvl9 Wiz that seems to have all 4 levels of spells open from AT and 5 levels of spells open from Wizard. According to another guide I should check the spell casting ability separately. The guide was from dmsworkshop.com and the post was named: things-you-didnt-know-about-dd-multiclass-spellcasting

Quote from the site:
"You Know And Prepare Spells Based On Each Class

This is the point where most people go wrong. According to page 164, when you are determining which spells you can learn or preparing a list of spells, you treat each class separately, completely ignoring the multiclass spellcasting section entirely. If you have one level of druid, it doesn’t matter how many other spellcasting levels you have, you prepare druid spells as though you were a 1st-level druid."

Wouldn't I be only be able to cast AT spells of levels 1 and 2 and wizard spells of levels 1-5? I checked the multiclass spell slots and it shows I would end up with: 4 lvl1 spell slots, 3 slots for levels 2-4, 2 slots of level 5 spells and 1 slot of 6th level spells (of which I would have none to actually cast?) at level 20.

So how does this all work exactly? I have played one campaign of 5e before, but I was an rogue/fighter so I'm not completely sure about the spell system in 5e. =/

[Man_Over_Game]

You're spot on. The spells you learn is separate for each class. The spell slots you cast is combined from each class. This means you can end up with spell slots that are higher than the spells you know. The idea is that you have a lot of energy, but not a lot of expertise as to how to best use it (like a car battery charging a toaster). You can still use that level 6 spell slot to cast another spell as a level 6 spell. This is important for spells that can be upcasted.

For example, Hold Monster is a level 5 spell, but the spell states you can target an extra monster for every level past level 5. So using it with a level 6 spell slot will mean you can target 2 monsters with a single casting.

[Rukelnikov]

Basically, each class "prepare" spells separately, but then both use the same pool of slots to cast from.

In your case, AT11 has 8 spells known, all of which can be lvl 1 or 2. Wizard 9 can, after each long rest, prepare 9+Int spells, or 13 in this case. And he can only prepare spells of lvl 5 or lower.

Once you have your list of prepared spells you can use your slots however you wish. Your 6th lvl slot allows you to cast a lower level spell with heightened effect, like a fireball.

[Kyou]

Hey, thanks for the quick replies! This clears things up. For a moment I thought that I had misunderstood and I could somehow reach the 4th level spells for AT because it uses wizard spell list or something and the build I found seemed to have 4th level spells chosen for AT.

[Keravath]

Hey, thanks for the quick replies! This clears things up. For a moment I thought that I had misunderstood and I could somehow reach the 4th level spells for AT because it uses wizard spell list or something and the build I found seemed to have 4th level spells chosen for AT.

An Arcane trickster gets 4th level spells at level 19.
A wizard gets 4th level spells at level 7.

A 10th level character with 3 levels of arcane trickster and 7 levels of wizard would have 4th level spells known from the wizard side and it would have the spell slots of an 8th level spellcaster (7 from wizard plus 3/3=1 from the arcane trickster). For comparison, a level 20 ... 13 arcane trickster rogue/7 wizard ... would STILL only have 4th level spells known as a wizard and up to 3rd level spells known as a rogue. They would not know any spells higher than 4th level. However, they would have the spell slots of a 7+13/3 = 11th level spellcaster which includes 5th and 6th level spell slots but no 5th or 6th level spells known.

So there are a variety of arcane trickster builds that will get 4th level spells at different points in their leveling up process.

[Ogeeogelthorpe]

Hey, I'm preparing for a new campaign my group starts tomorrow. I thought I'd try Arcane Trickster with some Wizard levels. I found a guide from this site. Can't post links yet but it's called Magique Filou: The Arcane Trickster's Guide

And the following build seemed good so I thought I'd try it with some changes:
THE RINGLEADER
Feral Tiefling Arcane Trickster 11/Diviner Wizard 9
ST8, DX20, CO16, IN18, WI12, CH10
ASI’s: DEX+4, IN+1 CO+1, IN+2, Resilient (CON)
Expertise: Arcana, Investigation, Insight, Stealth
Cantrips: Mage Hand, Booming Blade, Minor Illusion, Friends, Message, Mending, Toll the Dead, Fire Bolt
Spells: 1 – Charm Person, Tasha’s Hideous Laughter, Disguise Self, Find Familiar; 2 – Invisibility, Mirror Image, Hold Person, Blindness; 3 – Hypnotic Pattern, Major Image, Counterspell; 4 – Greater Invisibility, Evard’s Black Tentacles
(Wizard) 1 – Absorb Elements, Alarm, Shield; 2 – Alter Self, Levitate, Mind Spike; 3 – Clairvoyance, Fireball, Fly; 4 – Banishment, Fire Shield; 5 – Dominate Person, Scrying

I'm mainly confused about multiclassing and spells. In the list above, I see character of level 20 with lvl11 AT and lvl9 Wiz that seems to have all 4 levels of spells open from AT and 5 levels of spells open from Wizard. According to another guide I should check the spell casting ability separately. The guide was from dmsworkshop.com and the post was named: things-you-didnt-know-about-dd-multiclass-spellcasting

Quote from the site:
"You Know And Prepare Spells Based On Each Class

This is the point where most people go wrong. According to page 164, when you are determining which spells you can learn or preparing a list of spells, you treat each class separately, completely ignoring the multiclass spellcasting section entirely. If you have one level of druid, it doesn’t matter how many other spellcasting levels you have, you prepare druid spells as though you were a 1st-level druid."

Wouldn't I be only be able to cast AT spells of levels 1 and 2 and wizard spells of levels 1-5? I checked the multiclass spell slots and it shows I would end up with: 4 lvl1 spell slots, 3 slots for levels 2-4, 2 slots of level 5 spells and 1 slot of 6th level spells (of which I would have none to actually cast?) at level 20.

So how does this all work exactly? I have played one campaign of 5e before, but I was an rogue/fighter so I'm not completely sure about the spell system in 5e. =/

I like this build overall and having played an 11/9 Arcane Trickster Bladesinger I would suggest the following;

Dump charisma down to 8, add it to your starting CON instead. Your charm and illusion spells will make you good enough at the social side of things. This would allow you to get the resilient feat and still get the same max HP, and then you can get another feat tailored to your build. Sharpshooter is a great flat damage boost for rogue if you're going to snipe when you aren't slinging spells. Alert is always fun, as is observant. Tough is an extra 40hp total when you hit lvl 20, and another resilient invested in WIS won't hurt you either.

Swap out the ranged damage cantrips like Firebolt and toll the dead. Your ranged attack (likely from being hidden) won't trigger sneak attack with a ranged spell. You need a ranged weapon for it to hit such as hand crossbow or shortbow. And Most of the time attacking while hidden and shooting for 1D6+5 + 6D6 will hit for a respectable amount of damage. Save or suck cantrips like toll the dead are wasted on us. Add in Green flame blade for a little crowd control. It scales well.

Level 1 spells: my go-to spells of this level have been charm person, find familiar, shield, absorb elements, and Tasha's hideous laughter.
Level 2 spells: All good. Blindness/deafness can be nasty when you cast it while hidden. Misty step is great for escaping grapples. Mind spike is very meh for a 2nd level slot. You'll probably want to use these more for upcasted absorb elements. Also try sneaking in Shadowblade. You won't regret it.
Level 3 spells: Counterspell, dispel magic are excellent choices to have in your back pocket. Haste is super useful as a rogue. I've used a magical ambush hypnotic pattern on a crowd of yetis and wrecked the encounter. Blink can (and will) save your life when the enemy is a caster dropping cloudkill and you just vanish out of existence at the end of your turns. Thunderstep can help you squeeze out of a grapple that your low strength won't be able to avoid.
Level 4 spells: Charm monster can be fun, as can polymorph. Storm sphere can give you a bonus action ranged lightning attack to mix in with your normal ranged attacks. Greater invisibility is amazing at this level too. It pairs amazingly with all your spells and attacks.
Level 5 spells: Synaptic static and magical ambush combo amazingly well. So does steel wind strike. Your enemies will either have disadvantage on their save vs 8D6 psychic, or you'll have advantage on 5x 6D10 force damage attacks. Dominate person will help you wreck a social encounter or burn one of the boss's legendary resistances, same as hold monster.

The great thing about this build is the wizard spells being modular. You can swap them out depending on the situation. Collect all the rituals you can, as well. Things like water breathing, leomund's tiny hut and Rary's telepathic bond are excellent at any level. The ability to telepathically communicate with the party across any distance on the same plane can be the difference between a TPK or a victory.

[Malbrack]

I have a new character that I plan to build into a High Elf Arcane Trickster / Bladesinger. Our party is level 2 at the moment, and the rest of the group is a Barbarian with Sentinel feat, Great Weapon Master Paladin, Archery Fighter, and Grassland Druid. Realistically, the campaign will probably only run up to level 9 or so. I was thinking of Arcane Trickster 7 / Bladesinger 2. I'm currently 1 Rogue / 1 Wizard, with 16 Dex, 16 Int, 14 Con, 12 Wis, 8 Str and Cha. I took these classes at the first 2 levels because I wanted to get features from both classes online as soon as possible since I am filling in as the scout, trap/locksmith, know-it-all, ritual caster, and sole arcane caster for the group. I took expertise in Perception and Thieves' Tools, since the DM really likes Wisdom(Perception) checks. (Seriously. 6 of 8 ability checks in the first session were for Perception.) I've been talking to the Barbarian about possibly going Wolf Totem at level 3. That would give the Paladin and me advantage in melee, which should be a pretty big power boost.

I'm dual wielding short swords at the moment because 3d6+3 is too good to pass up at levels 1 and 2. I'll switch over to a rapier once I pick up Cunning Action. For cantrips, I have Minor Illusion (from High Elf), Prestidigitation, Booming Blade, and Green Flame Blade. I didn't bother with a ranged cantrip, since I can just use a bow for more damage. For level 1 spells, I picked up Shield, Fog Cloud, Disguise Self, Find Familiar, Detect Magic, and Comprehend Languages. I know Comprehend Languages is sort of niche, but it makes sense for my character. She's wildly curious and she wants to know all the things. She would break into the houses of rich people to steal their books, read them, and then return them. I don't think I am going to have access to Absorb Elements. And I left off Charm Person and Tasha's Hideous Laughter, because I plan to pick those up as free choices from Arcane Trickster 3.

Anyway, I have a couple questions:

1. At level 3, should I take another rogue or wizard level first? Basically, which is more urgent: Cunning Action or Bladesong? I'm leaning toward Wizard 2 first.

2. By level 5, I plan to be Arcane Trickster 3 / Bladesinger 2. At that point I would have level 2 spell slots, but only level 1 spells. What would be my best use of casting a level 1 spell from a level 2 slot? From the spells I have picked, none of them really benefit from upcasting. (Fog Cloud can be upcast, but I'm not sure how often I'd need a bigger cloud. Charm Person is going to be out of combat only for me until Magical Ambush.) Should I look into a spell like Thunderwave for this purpose?

[Man_Over_Game]

Anyway, I have a couple questions:

1. At level 3, should I take another rogue or wizard level first? Basically, which is more urgent: Cunning Action or Bladesong? I'm leaning toward Wizard 2 first.

2. By level 5, I plan to be Arcane Trickster 3 / Bladesinger 2. At that point I would have level 2 spell slots, but only level 1 spells. What would be my best use of casting a level 1 spell from a level 2 slot? From the spells I have picked, none of them really benefit from upcasting. (Fog Cloud can be upcast, but I'm not sure how often I'd need a bigger cloud. Charm Person is going to be out of combat only for me until Magical Ambush.) Should I look into a spell like Thunderwave for this purpose?

I think Bladesong will be more of a benefit. The extra AC at this low of a level will be a massive boon.

For upcasted spells, I'd really look into Sleep, False Life, or Magic Missile. Thunderwave, as you mentioned, is another good option.

[Ogeeogelthorpe]

I have a new character that I plan to build into a High Elf Arcane Trickster / Bladesinger. Our party is level 2 at the moment, and the rest of the group is a Barbarian with Sentinel feat, Great Weapon Master Paladin, Archery Fighter, and Grassland Druid. Realistically, the campaign will probably only run up to level 9 or so. I was thinking of Arcane Trickster 7 / Bladesinger 2. I'm currently 1 Rogue / 1 Wizard, with 16 Dex, 16 Int, 14 Con, 12 Wis, 8 Str and Cha. I took these classes at the first 2 levels because I wanted to get features from both classes online as soon as possible since I am filling in as the scout, trap/locksmith, know-it-all, ritual caster, and sole arcane caster for the group. I took expertise in Perception and Thieves' Tools, since the DM really likes Wisdom(Perception) checks. (Seriously. 6 of 8 ability checks in the first session were for Perception.) I've been talking to the Barbarian about possibly going Wolf Totem at level 3. That would give the Paladin and me advantage in melee, which should be a pretty big power boost.

I'm dual wielding short swords at the moment because 3d6+3 is too good to pass up at levels 1 and 2. I'll switch over to a rapier once I pick up Cunning Action. For cantrips, I have Minor Illusion (from High Elf), Prestidigitation, Booming Blade, and Green Flame Blade. I didn't bother with a ranged cantrip, since I can just use a bow for more damage. For level 1 spells, I picked up Shield, Fog Cloud, Disguise Self, Find Familiar, Detect Magic, and Comprehend Languages. I know Comprehend Languages is sort of niche, but it makes sense for my character. She's wildly curious and she wants to know all the things. She would break into the houses of rich people to steal their books, read them, and then return them. I don't think I am going to have access to Absorb Elements. And I left off Charm Person and Tasha's Hideous Laughter, because I plan to pick those up as free choices from Arcane Trickster 3.

Anyway, I have a couple questions:

1. At level 3, should I take another rogue or wizard level first? Basically, which is more urgent: Cunning Action or Bladesong? I'm leaning toward Wizard 2 first.

2. By level 5, I plan to be Arcane Trickster 3 / Bladesinger 2. At that point I would have level 2 spell slots, but only level 1 spells. What would be my best use of casting a level 1 spell from a level 2 slot? From the spells I have picked, none of them really benefit from upcasting. (Fog Cloud can be upcast, but I'm not sure how often I'd need a bigger cloud. Charm Person is going to be out of combat only for me until Magical Ambush.) Should I look into a spell like Thunderwave for this purpose?

Thunderwave is mediocre for arcane tricksters because cunning action allows a bonus action disengage. Thunderwave shines most when you need to push people back for an escape.

Bladesinger AC boost is good anytime. With studded leather armor and 16 dex/int you'll have an AC of 18, very good at tier 1 tables and respectable in tier 2.

Your best use of level 2 spell slots at that level is boosted absorb elements if you get hit with burning hands, scorching ray, etc. That'll add 2D6 of that element's damage type to your next attack. Cause fear can be cast on 2 targets when upcast to 2nd level, as can charm person. You can have fun with catapult as well if you have a battlemaster fighter disarming people and you start launching their own weapons at them or away from them.
False life is decent in tier 1 but once you get into tier 2 it's not worth preparing.

[McSkrag]

I have a new character that I plan to build into a High Elf Arcane Trickster / Bladesinger. Our party is level 2 at the moment, and the rest of the group is a Barbarian with Sentinel feat, Great Weapon Master Paladin, Archery Fighter, and Grassland Druid. Realistically, the campaign will probably only run up to level 9 or so. I was thinking of Arcane Trickster 7 / Bladesinger 2. I'm currently 1 Rogue / 1 Wizard, with 16 Dex, 16 Int, 14 Con, 12 Wis, 8 Str and Cha. I took these classes at the first 2 levels because I wanted to get features from both classes online as soon as possible since I am filling in as the scout, trap/locksmith, know-it-all, ritual caster, and sole arcane caster for the group. I took expertise in Perception and Thieves' Tools, since the DM really likes Wisdom(Perception) checks. (Seriously. 6 of 8 ability checks in the first session were for Perception.) I've been talking to the Barbarian about possibly going Wolf Totem at level 3. That would give the Paladin and me advantage in melee, which should be a pretty big power boost.

I'm dual wielding short swords at the moment because 3d6+3 is too good to pass up at levels 1 and 2. I'll switch over to a rapier once I pick up Cunning Action. For cantrips, I have Minor Illusion (from High Elf), Prestidigitation, Booming Blade, and Green Flame Blade. I didn't bother with a ranged cantrip, since I can just use a bow for more damage. For level 1 spells, I picked up Shield, Fog Cloud, Disguise Self, Find Familiar, Detect Magic, and Comprehend Languages. I know Comprehend Languages is sort of niche, but it makes sense for my character. She's wildly curious and she wants to know all the things. She would break into the houses of rich people to steal their books, read them, and then return them. I don't think I am going to have access to Absorb Elements. And I left off Charm Person and Tasha's Hideous Laughter, because I plan to pick those up as free choices from Arcane Trickster 3.

Anyway, I have a couple questions:

1. At level 3, should I take another rogue or wizard level first? Basically, which is more urgent: Cunning Action or Bladesong? I'm leaning toward Wizard 2 first.

2. By level 5, I plan to be Arcane Trickster 3 / Bladesinger 2. At that point I would have level 2 spell slots, but only level 1 spells. What would be my best use of casting a level 1 spell from a level 2 slot? From the spells I have picked, none of them really benefit from upcasting. (Fog Cloud can be upcast, but I'm not sure how often I'd need a bigger cloud. Charm Person is going to be out of combat only for me until Magical Ambush.) Should I look into a spell like Thunderwave for this purpose?

I am currently playing a melee focused Arcane Trickster 6 / Bladesinger 3 in Adventurers League. Super fun build to play.

Based on my experience here are a couple things you might consider:

• Take a 3rd level of Bladesinger early. I went 3 AT / 3 BS. This gives you 2nd level spells, more spell slots, and the ability to add 2nd level spell scrolls to your spellbook. There are a lot of excellent level 2 spells for you: Invisibility, Shadow Blade, Mirror Image, Hold Person, Misty Step, Suggestion, Web, Blindess/Deafness, Levitate. The trade off is delaying your AT progression and ASI's - but for me it's been well worth it.
• Use Shadow Blade + Booming Blade to up your damage especially in dim lighting.
• Get a +2 or +3 shortsword as soon as possible. Against high AC targets you can upcast Shadow Blade and use the +2 shortword in your offhand to give you 2 chances to land your sneak attack. You can't do this with a rapier.
• When you get high enough level take the Sentinel feat and pair it with Mirror Image. If an enemy attack an ally next to you or attacks you and hits one of your mirror images you get to attack them back with sneak attack damage.