User blog comment:Skeith9/Heroic Spirits Speculation/@comment-24762556-20140624072224/@comment-24762556-20140625035743

If friggin Nursery Rhyme, Frankenstein's Monster and Jekyll & Hyde qualifies as legit Servants in "canon", I don't see why the good witch wouldn't.

Besides, several posts down and you can already see people throwing DBZ characters around as suggestions, so there's that.