Arena resets every Saturday.
Receive rewards according to points earned.
Yay, an avatar, but will expire at the next reset.
Arena participation is important because we can obtain Arena chest rewarded after winning a challenge against other players.
In the chest, we may find these two splinters. Just why do we need these splinters?
Once is enough, but battle more to obtaon the Arena chest.
The Advanced magic splinter, 10 of it will unlock your hero's Extended Skill slot. You could see this when you view your hero using the Hero menu (top left of the screen) The other splinter is used to research the extended skill.
Yep, the more reason to battle in the Arena.
And also, you can complete the Daily quest - Be victorious 1 time in the Arena.