Also, though it doesn't matter here, it is usually a good idea to say how you are gaining control of something.
As soon as you transform Jace, he will re-enter under the control of his *owner*. This is due to the fact that the ability says to "return him to the battlefield transformed under his owner’s control". There is never a time when you will control him while transformed and your opponent will control the planeswalker version of Jace.
And if an effect doesn't state under whose control a permanent will enter the battlefield, then by default it enters under its owner's control.
You may be surprised, but that is actually incorrect.
110.2a. If an effect instructs a player to put an object onto the battlefield, that object enters the battlefield under that player's control unless the effect states otherwise.
I believed the same as you did until I fell upon the unusual case of Homura, Human Ascendant, which actually returns under the control of the player who controlled it as it died since they control the death trigger and they are instructed to return it. The immense majority of effects that instruct players to put permanents on the battlefield specify under whose control, so we seldom have to wonder about this, but Homura is a weird exception, which would have received clarifying errata a long time ago if it wasn't an obscure card that almost no one plays.
I'm a former judge (lapsed), who keeps up to date on rules and policy. Keep in mind that judges' answers aren't necessarily more valid than those of people who aren't judges; what matters is we can quote the rules to back up our answers. When in doubt, ask for such quotes.
Ah yes, right. I think that rule was changed many years ago. It used to be as I said, and I still apparently haven't adjusted to the new order of things.
Jace, Vryn's Prodigy
Also, though it doesn't matter here, it is usually a good idea to say how you are gaining control of something.
As soon as you transform Jace, he will re-enter under the control of his *owner*. This is due to the fact that the ability says to "return him to the battlefield transformed under his owner’s control". There is never a time when you will control him while transformed and your opponent will control the planeswalker version of Jace.
Former Rules Advisor
"Everything's better with pirates." - Lodge
(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
(Girl Genius - Fairy Tale Theater Break - Cinderella, end of volume 8)
Former Rules Advisor
"Everything's better with pirates." - Lodge
(The Gamers: Dorkness Rising)
"Any sufficiently analyzed magic is indistinguishable from science."
(Girl Genius - Fairy Tale Theater Break - Cinderella, end of volume 8)