My opponent and I each have 5 1/1 soldier tokens on the battlefield.
My opponent casts Nomads' Assembly, I cast Commandeer targeting the Nomads' Assembly and gain control of that spell. No other spells are cast, nor any other shenanigans are performed during the rest of the turn.
Once the spell resolves, I have 10 1/1 soldier tokens on the battlefield, and the spell is exiled. Do I still control this exiled spell? Or does my opponent now control this exiled spell? I think rule 400.7 is the proper rule, but I'm not seeing this interaction explained.
Specifically, my opponent owns the Nomads' Assembly while it is in exile, but do I control it? Or does he control it as the card moves into exile? When does the spell return to play? And who gets to double their number of tokens?