I'm calling it now

Just for good measure, because I've been thinking this since the beginning and it's been solidified pretty well, so I feel emboldened to call it: I guess Solderet is no more.
I mean, it was my first guess right at the beginning, because I literally have similar plot line planned in one of my own stories, therefore, it was low hanging fruit to think in that direction. But I believe he more or less sacrificed the last of his power to regress him.
It would explain why the compass didn't show Jin on the map and I believe it might be impossible to take his contract away from him, because there can't be a new contract made. Either, he basically took the chair of Solderet himself, or just the rest of his powers, but there is no god of shadows anymore, that's my call. Either that, or he sleeps, like Murakan did, either way, no new contract after this one, so no switching possible.
And can he please get rid of that Joshua-ass hairstyle?