Paladin of Tyranny crunchy and fluffy advice

[Man on Fire]

I got new idea for a character today and would love to hear a bit of an advice on both crunch and fluff on how to make it work.

Paladin of Tyranny (LE) who serves Lawful Neutral God that accepts both good and evil followers. By this god's orders he is serving now LG Liege and is bound to uphold Knight's Code of Chilvary and it ovewrites usual Paladin of Tyranny's Code. He despises it and actually looks down upon common folk he, as a knight, is bound to protect (think of him as guy who sees peasants as no better than cattle), but is so fanatically devoted to the order and his god that he doesn't question the orders. So he goes around and tries to do these things

Spoiler: Code of Chilvary

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To fear God and maintain His Church
To serve the liege lord in valour and faith
To protect the weak and defenceless
To give succour to widows and orphans
To refrain from the wanton giving of offence
To live by honour and for glory
To despise pecuniary reward
To fight for the welfare of all
To obey those placed in authority
To guard the honour of fellow knights
To eschew unfairness, meanness and deceit
To keep faith
At all times to speak the truth
To persevere to the end in any enterprise begun
To respect the honour of women
Never to refuse a challenge from an equal
Never to turn the back upon a foe

While inside being still rotten bastard. Sometimes he might twist the interpretation to his own end, but only when he has quote from his god's holy texts to back himself up. Maybe I think of kind of playing him as a a bit of a parody on "overzealous paladin" type of thing in that he is just like that, because he is a sadistic, evil bastard, I'm not yet sure.

Anyway, questions I'm wondering about
1) Fluff Question - what kind of god could be most fitting for this character? I'm talking in general but also Forgotten Realms in particular as character I'm playing in Forgotten Realms game right now almost always ends up at the verge of death, so I'm most likely to bring this one as an replacement when he finally bites it.
2)Any advice about the build? Especially decreasing the MAD? I thought of either going with Serenity (rather not because I think this gu should be quite charismatic) or give up on spells and try to combine him with Martial Paladin (is that even possible? I cannot find what sourcebook Martial Paladin is). Maybe I should go Claric/Prestige Paladin (with some class features replaced to be like Paladin of Tyranny) instead, if GM allows it? If not, what would be good Prestige Class for this character, aside Blackguard (of which 2 levels-dip is a given)? I'm open for Psionic and ToB but would be interested in build without them because of abovementioned game in which I'm likely to play this character - GM has bad experience with psionics and banned it and while he lieks ToB he won't allow taking levels of TOB classes if other players doing meele are doing lower tier classes (and right now meele in this group is my rogue/swashbuckler, Bear Totem Barbarian and vanilla Ranger and neither Barbarian or Ranger players are into ToB). Also, any advice about race (aside Lesser aasimar or maybe even regular one)?