ask DM if you can pick up to 2 flaws for bonus feats at first level, makes finding the right build easier.
paladin 5 / hunter of the dead 5 / boneknight 5 / (bone knight to infinity)
bone knight is a ba paladin PrC from Eberron 5 Nations; don't take any more levels of hunter of the dead, the best ability it gets is the 5th level true death ability - slay them rejuvenating undead forever if your attack drops them to 0 hitpoints, no gaseous form for the vamps, no phylactery poofing for the liches, no going back to the corpse to rise again for ghosts, just plain destroyed at 0 hitpoints.
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scout 3 / ranger 12 swift hunter build, pick elf, go elf racial sub for ranger 1 pick undead as your favored enemy (bonus = +3 instead of +2), NG with true beleiver for Ehlonna, buy some Raptor Arrows (MIC), get a splitting composite long bow, go to town; greater many shot every round no need to worry about restringing the raptor arrows.
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Warlock 15 / (warlock infinity)
--be the guy with at will spell-likes that can make you the guy able to do what every one else cant; like shatter at will, fly at will, dimension door at will, acid/fire/cold damage at will, evard's black tentacles at will, dispel magic at will, 250 ranged weapon at will, invisibility at will, etc...
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have you looked at Magic of Incarnum? can make some beastly characters that hate undead from that book.
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Fighter 15 (lock down build), just put bane undead on your spiked chain a bunch of times for some beastly bonus damage dice (if dm allows), or just once; control the battlefield around your party. (don't forget ghost touch!)
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Exalted Human Monk 15 (meaning take lots of exalted feats like vow of poverty, touch of golden ice, nimbus, stigmata, etc..) combined with the good feats from Libris Mortis to help keep you safe from undead attacks.
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Wildshape Ranger 9 / Nature's Warrior 5 / Warshaper 1 - be what you want when you want to whoop butt
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Fighter 1 / Barbarian 6 / Frenzied Berserker 8 - uber charger build with a twist, take Robilar's Gambit at 15th level, turn it on before you go nuts (cuz it isn't really tactical, its actually non-tactical to allow your opponent to hit you so you can hit them, perfect for a crazy dude who don't feel pain) that way after you charge and kill your target and murder your cleave target, any one else that swings at you gets thumped hard.
hope these help, rumble
