Minor Role: Cosplay is a non-Affinity vanilla card used usually by beginner players. He may not be summoned very often, so suitable for those that want a minor role. 

Card Lore: Unable to afford any fancy costumes, this creature makes do with a cheap, worn out blanket, "cosplaying" as a ghost and will often go to conventions. No one is sure what his real identity is, though. 

Personality: Cosplay has a very tired and defeated personality. He's one of the summons that actually speaks words in battle. 

Voice: I imagine his voice sounding tired, monotone (in a comedic way) and very disinterested in what's going on. It could even be "Garfield-like"