RPG gave some info on Ace. Harry has no idea, Ace just fell off the radar. I'll have to reread, it might be that he's dead...
Ace is dead *In joke*. Ah, I really hate Butcher for using that cool name in that character

.
Hmmm... Now that you're bringing him to question, I wonder if he's going to come back in the next books?
That "I'm a lazy writer" thing is making me paranoid. I mean,
more.