Dark Alliance II occurred to me, but I wasn't sure if it was a good suggestion given its age and very high used (nevermind new) price.
Dark Alliance II's unofficial EverQuest-themed sequels, Champions of Norrath and Champions: Return to Arms both let you play as a Dark Elf Shadowknight. In addition to weakening and poison-based magics, they can summon undead helpers to fight for them.
If you can get a copy of any of those three for <$20, they're worth playing.
Bonus (mediocre) suggestion: Undead Knights for PSP.