The Thundering Mephis teleports frequently, though, making it a harder boss to predict.
From there, fly down to the northeast until you’ve found the boss.
It’s best toavoid having Electro Resonators on your team at allbecause of this.

Once you’ve prepared your team, head down to the battlefield to start the fight.
The Thundering Mephis teleports around the arena a lot, making it hard to track.
It’ll fling lightning that quickly creeps across the battlefield toward you.

Whenever you notice this,dodge the lightning in time.
This is a great fit for any Electro DPS character, like Calcharo or Yinlin.
Done fighting the Thundering Mephis?