I can't run multi-battle in Brutal difficulty. It has 2 issues:
1. It only ever runs 1 of the multi-battles then will say it's complete after the first round.
2. Only 1 champion will show in battle no matter how many champions I choose to battle.
I've been dealing with this problem for almost a week now. I'm paying the monthly subscription for extra multi-battles and the feature doesn't even work. PLEASE FIX NOW
Ok, I'm gonna take a stab at this since everyone seems to being having the same issue.
From what I can gather/read in the posts about this... This was probably intended. A "feature" to say... Welcome to the coder life. I live it. Not games, but you get the point.
1) The leader seems stays no matter what. Usually that's the maxed character.
2) Any other max level person is removed from the party. This occurs at the start of any of your multi battles. First one, second or last.. whatever. (I've had a character removed half way into multi battles as soon as he hit max) This is probably why you still see the removed character at the end of the battle summary. To tell you it was part of your selection, maxed out then got removed.
I'm guessing the intention was that someone thought it was a good way to make sure that your characters getting leveled got the most EXP out each round.
IE. Let's say that a Round is worth 10k. 4 toons means 2.5k each.
Multi battle commences, finishes and everyone gets 2.5k
A toon hits max and on your next round is removed (not the leader) and now assuming you complete the round everyone gets 3.3k exp. More EXP! Yay!! Too bad the guy you had might have been needed to actually finish. I've been running a map where I need 2 max level guys to finish it when the others will eventually die.
So... we can gather their intention is that you're using 1 max character to carry 3 others. That the single Leader/Max character should be able to solo the entire round.
While intention was nice, most of us don't do that from what I can tell. We use 2 or 3 max toons to complete later maps to dump the most exp into 1 or 2 characters while also reaping the benefits of getting higher gear/money.
That seems to be the situation from what I can tell. These are just my observations/opinions. Most of us seem to want this "feature" reverted though.