The original recruit Angels characters are all at Level 1. Players need to spend a certain amount of ANGEL/GEM to level up your characters. The higher level, the more reward you receive from you characters.
Level is one of the most important attributes in-game, it will directly increase your character attributes and reward
Please note: when you upgrade your high-level Angels character, there’s a possibility of failure. If you fail to upgrade, your Angels character will disappear permanently.