(Fate Series Crossover) Servants From Different Fandoms

Wally/Waldo (Assassin)

I know, I know. Sounds ridiculous but just IMAGINE. Wally's (or Waldo in some places) special skill can be to walk around practically anywhere and just never be seen. I don't know about you, but I remember pouring over the "Where's Wally" books and legitimately staring directly at him and still not being able to 'see' him but in a way that I don't even realise he's there. He'd be the ULTIMATE ASSASSIN! The other servants won't know that they're being killed till they feel a knife through their chest, or whatever. Besides all this, I think it'd be pretty damn hilarious to summon Wally as a Servant.