I love the battling in this game, and I'd love to do more of it without being restricted by stamina. It would be nice if we had a mechanic that allowed us to perform battles to test out teams and all that, but with ZERO
It would allow players to use monsters that they normally wouldn't due to the risk of wasting stamina and rewards, and it would give others stuff to do while they wait for other things to reset.
There could be some customisation to what teams you'll fight, you could simulate war teams and PVP teams with restrictions in the arena, and it would allow you to try monsters in a lot of situations to see how they would fare with others.
For example, say you wanted to go in a fight with Underworld, Family and Fire restrictions. With the arena, you could make a team to fight another team with the same restrictions and rune levels. So you could have Famperium, Galante and Ingenica, while the other team could have Violet, Shallinar and Keithor.
Please let me know what you think of this idea, and I'd love to discuss with others about this.