Ch'en the Holungday banner

Ch'en's alter form was perhaps the most controversial character in the game. There were many reasons that go far beyond the scope of this guide, and we don't need to discuss them here, but it's notable how far powercreep has gone that Ch'en the Holungday is no longer considered to be especially top-tier! In any case, while that is definitely true, she's still a powerful DPS unit that's worth fairly high consideration. Her only skill really worth considering for Mastery is her S3. It's by far her best skill despite a fairly long cycle, since it's the one that integrates most of the things that once made her special. It has high DPH, a large ammo pool for a huge total damage, and pretty solid control. But surprisingly, the Mastery gains on it are actually fairly unimpressive. S3M1 boosts her snare and DEF ignore slightly, but not enough to even warrant a breakpoint label, and she only otherwise gains a tiny amount of SP cost (less than 10%) and a standard amount of damage. That's still worthwhile since you of course want to maximize the damage on your DPS units, but considering Ch'en2's lower place in the meta, it's nowhere near the priority it used to be. Pass on her other skills