Once upon a time when five stars ruled the world.
You could level up adrenaline rushes with Adens, trait trainers (hunter, leader etc.) and you could also lvl up ARs with normal characters (1*,2*,3*,4*,5*)
AND we had to focus only on ARs!
Fair enough, we could lvl up ARs with Liliths and Adens, but it’s still not the same, we train (cook) characters to lvl up 6*s, but can’t lvl up their rushes, and we also need to lvl up active skills too.
Therefore, we need an easier way or more of the current trainers to lvl up ARs and active skills.