Am I able to merge characters with the same stars?
And if I change a 3 star to a 4 star, does the SP carry over?

Arena Quests have been added. Now better chance to get more feathers.

Also the 10,000 feathers got awarded.

I hope those arena quests are available every week it resets.

Edit: or not, just realised there a hard mode and lunatic mode quests too for arena.

They have expire dates. I'm pretty sure new quests will replace them.

Who did you draw?

Arena battles can only be chained 7 times to get a max score. So make sure you use as many of the featured characters as possible to get a good score.

Is it just me or are mages quite weak?

If one of your characters dies during combat, they do not keep the experience they gained. So try not to die.

I thought that was only the case when you lose the battle...?

They're kinda glass cannons, but minus a few units, like pegasus knights and theives, they do some heavy damage to most units.