3.P Gestalt -Antipaladin/Black Blade Magus Optimization

[Rickshaw]

Playing a CE goliath Antipaladin/Black Blade Magus (scimitar focus) with the Death Knight template. Any suggestions for optimization? I couldnt really find any prestige classes that go well with that sorta thing, which is why i'm askin the playground! even any feat paths that might be important?
I got super lucky with my rolls (3 18s :smallbiggrin:)here is his stats.

Str - 26
Dex -13
con - (undead)
Int - 22
wis -13
Cha - 20

EDIT: I picked these classes because I wanted to be able to kill the flood of paladins coming for us. and fill the tank slot in our party.

[deuxhero]

Paladin of Tyranny 8/Blackguard 4/Paladin of Tyranny 4/Hexblade (Dark Companion) 4 for -8 to all enemy saves, charisma to saves 4 times and books to the head 1 time?

Magus//Antipaladin isn't really my pick for a good combo due to separate attributes (It's OK due to the largely passive boosts though). Warblade or Factotum seem better.

Duskblade could be an option too depending on how the DM stacks things.

[Rickshaw]

My thinking was that I could take the fiendish boon with my black blade. so that, combined with the magus arcane pool thing that buffs my sword, all comes together to make a crazy good sword. also since the campaign revolves around us being marked by Pelor (as in he wants his followers to kill us) I figured it would be a good idea to make a paladin killer (the smite good, the touch spells from magus, all the vs paladin abilities antipaladins get, etc.)

Edit: perhaps I should have made this thread about how to make the best paladin/cleric killer. or I could just make a new thread...