He's a half-elf bard who is secretly a thrall of the Demon Prince(ss) Malcanthet. He is currently manipulating the party into releasing the imprisoned half-god son of the Demon Queen (long story) from its tomb deep below the earth. The campaign is fairly long-term, and I didn't bother writing stats for the bard when he was first introduced, because I knew it would be a long time before the players ever had to confront him in any direct fashion.

Well, that time has almost come, and every time I try statting him up, it just doesn't pan out. The PCs are about 7th level now, and I want the bard to be a much tougher fight than they're initially expecting. But a bard's main base utility is as a support character, and that's not the direction I want to go.

So, then, any ideas for how to stat an effective bard villain for a party of six 7th level PCs? I fear that I painted myself into a corner by conceiving him purely for the flavor, instead of giving more thought to the mechanical difficulties in store.