Thank you for continuing on with this discussion, guys. It makes me think I really have something potentially great here. Hopefully I can meet that expectation

You’re both right. I need to tie in the “split consciousness” to the logline so it’s more than just intriguing, but integral.

In a sense, Dkpough1, his split consciousness is, all three. You might compare it to being a young clone of himself (a character). He needs to raise (a goal) and train it to be just as or more powerful as/than he is (tool).
Keep in mind, this is separate from the pupil in the common realm. He has to train them both, then they have to use their combined powers to open a portal that would release him from this alternate realm.
Now, I didn’t list this, because it gets complicated, but one of the primary obstacles is that the Mage and the alternate realm that they are in is tied to an artifact in the common realm. As long as they are within proximity to each other, their powers increase, and, as well, they can communicate more easily.
Back to the [clone]…just like with the artifact, their individual powers increase when they are in proximity to each other.

One common obstacle to be expected is frustration with the training, causing one or more to walk away. This would weaken the powers of each character, leaving each to work on their own, with their limited powers, to defeat their individual obstacles and villains.

I’m a bit frazzled with other things right now, so I’m not thinking clear enough to write up a satisfactory draft. I’ll return to this when I get a chance.