Re: FFVI cast

Terra is a powerful mage with full access to black magic and summons. Her sword and heavy armor access is mostly for niche equipment since she'll often end up with a rod and a hat to maximize that magic. Her support ability access mainly enables some very powerful use of her relics if you get lucky enough to have them.

potentially one of the most powerful mages in the game

I will say no more for to gush too much or to criticize this one brings the righteous fury of one of our own.

Locke is a thief, he's quick and has access to some useful tools like steal power. He also gets the awesome celerity tempoflurry which will be solid damage until you can get Thief's revenge for even more awesome. When we lacked their abilities he was rather weak without relics, now he's pretty strong.

One of the top thieves in the game

Edgar is your knight in emerald armor. He isn't top of his class at much, though his machinist abilities will be handy in those rare times an enemy is weak to a status. Knights tend to be very strong overall but VI has other knights that outshine him. Still a sold guy though.

Sabin is a monk - like Locke he's inproved with new abilities. Chakra and kick are solid wave clears until you can upgrade to meteor crush and fires within for strong damage. I find his relics all over the place.

Celes - knight, mage, healer, spelblade. Has one of the few truely useful default SBs and some amazing relics. Celes is one of the best magic tanking knights in the game - and relics make that even more so. Very versatile though strongly stlanted towards physical combat.

Gau - they didn't know what to do with him. Poor stats, a terrible SB gimmick, only shiny part is his access to celerity and combat at full but by the time anyone realies how potent that combo is they'll have relics for enough people Gau will have to stay in the velt. Might as well not have bought that dried meat.

Cyan - samurai and that's it. Cyan's big gimmick early on was retaliate (because he was a 5* samurai with no samurai abilities to use for a long time). The other problem is him Being very choosy with weapons. He will use daggers and Katanas. Nothing else. Samurai as a class has improved since then with strong abilities like Hailstorm in the mix.

Setzer - I hope you like him because he is your support character meaning that as you go into late game you will be requiring either him or Mog in your team. Setzer also has mechanic access but you won't care by the time you can hone 4* abilities you'll be loving him only for those breakdowns.

Mog - white magic and dancing. Mog is an okay healer and a great dancer. Dances to AoE support debuffs but without any damage - so as you can guess they're preferred in fights with many enemies or fights where the enemy counters. The rest of the time you probably want damage going out.

Relm - the other choice for healer (and the stronger one). She also has summon options if you feel the need for damage which isn't a Dia spell. Relm is a top notch healer and could easily serve an A team well, especially with relics.

Strago - the magical Gau. He isn't great at anything. He isn't terrible early on and is getting an awesome burst soon, but he is really second tier within VI let alone in the greater game.

Shadow - a physical ninja character in a game where ninja heavily favors magic. He isn't bad at all (far from) but he'll want some niche weapons to really get the most out of his abilities.

Kefka - mage, bard, dancer, darkness. Everyone's favorite diety plays second fiddle to Terra in the mage game with options which are more flavor than substance until you get the orbs for darkness skills. These can pack a wallop and are rarely resisted - but also rarely advantaged.

Leo - slower, better, Cyan. Leo combines knight access with partial samurai to pull off a combo know as "tauntilate" . With Draw Fire and retaliate all physical attacks will go to Leo where he avoids them and counters (does not work on AoE or NAT type physical attacks).

The VI cast is big but off the top of my head I don't think I missed anyone.