With GM's approval you could use homebrew material, like here (http://www.dandwiki.com/wiki/Kitsune_%283.5e_Race%29) in example. Altough it is quite weak choice as it's a +1 LA race and no HD.<br/><br/>But as said your monster appearance is entirely up to you; you could take succubus as a base demon (or pleasure devil) and then build it from there with vampire, unholy scion and so forth. But to keep up trickster (scoundrel) feature and get charisma for AC and saves I would use gloura (http://www.wizards.com/default.asp?x=dnd/ex/20031003e), underdark fey and they are 7th level bard spellcasting wise (and some lovely other stuff in it and it is CR 7 only). Just remember pick bonus HD to get close to epic levels before class levels.