It's a little hard to say just what constitutes 'gone' around here. It's a complicated mess of Second Magic, but I wouldn't count out the possibility that he could show up here as well.

[Waver was struck by a distinctly awkward sensation; intuition (and a little common sense) told Waver he already knew who Karna's Master was. He was starting to feel like he was on the other side of every conversation he'd had with Diarmuid here. Someone who didn't remember all they had been through together, someone who was the same and yet wasn't at all.]

[Idly he wondered if his Lancer was ever this much at a loss for what to do about him.]

I--he does, but he's more my friend than my Servant. He's a Lancer-class by the name of Diarmuid ua Duibhne; if you run into him here I'm sure he'll help you get the idea of how this place works better than I could.