Every time I think I'm out...
Anyway, let's take a look at what we have here.
1) Are you known in the community? Yeah, I know your name, at least, and I'm barely considered to be here.
2) Can you write? This is a more difficult question. SPaG is fine, which I would expect given that you have betas, so good there. However, you have a problem with story-flow. I think this may be what hS was talking about. Your characters go from one emotion to be next without passing the intervening space (teleporting emotions?).
An example of this would be when Arden goes immediately from sombre and depressed to totally ecstatic because his partner points out the bed that was in full view the whole time. He could see the bed, but he didn't react to it until it was pointed out to him, and then it was a sudden full reversal of emotion. It is all very sudden and gives the impression that each thought and action is totally independent of what came before it. And I know you mention this in Arden's bio, but it isn't limited to just him. Even if it was, he is incredibly jarring on his own. You'll want to work on the flow, going forward.
3) Your characters. This is where we run into some big problems.
Jace "Shiny" Beleran - One of your two characters is (arguably) the main protaganist of the MTG story. That's not a particularly encouraging start. Add to that the fact that Jace is incredibly intelligent and powerful even beyond his mental magic. That's part of what being a Planeswalker is: semi-phenomenal, nearly-cosmic power, itty-bitty living space. This is a man who beat an infinitely-old, eldritch abomination at chess without any magic at all. He might be the greatest mind in the multiverse. AND he has powerful magic at his disposal.
Also, what time period is he supposed to be from? According to the bio, he just ran afoul of Alhamaret and lost his memory, but that point isn't depicted on any Jace card that I'm aware of (and I did check). There's Vryn's Prodigy where he is a kid before the Sphinx took him in, and everything else is after he lost his memory and grew up on Ravnica. And none of the cards have grass in the picture, so that didn't help pin it down.
All of this is to say, there are major problems and I'm really not comfortable with this character, at all.
Arden - Seems fine enough. I just don't recall ever reading that Krynn magic is addictive. Some mages went a little nutty when the power got turned off that one time, but that was because the magic was all they had in their life, and they didn't know how to cope when they thought it was gone for good. In the grand scheme, this is a small detail that can be easily adjusted.
So, verdict time. Permission denied, for a couple of reasons.
For one, Jace has to go. Create a new character that isn't a near-god-level protagonist in the story they come from. The idea of a card being transformed into a living being isn't a bad idea, just stay away from the Planeswalkers and probably the Legendary Creatures as well. There is still plenty of room to play there. Maybe the character is a Deputy of Acquittals, or a Goblin Test-pilot, or a Simic Guildmage. The multiverse is a big place.
Secondarily, you need to work on the flow of your stories. The lack of clear progression from point A to point B can be off-putting, and you want your audience to be able to follow along.
There are good parts of your request so fix these few problems and re-apply. You are probably not far off.
-Phobos