It's not even hard at all, but it's almost impossible to clear without specific units.

So far I can consistently clear it with the following team

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Verdandi 6*

Deimos 4*

May 1* (I don't have Esna)

Karen 4*

Verdandi 6* Friend

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But sometimes its still not enough to clear the DPS check. The last boss even aborbs damage from fire units. In my opinion, this is terrible design. The increased damage to non-water units is too much of a limiter.

The dungeon requires no creativity at all, unlike the previous ones wherein you can substitute units and find other ways if you don't have the recommended ones. Kristian could be grinded by 2 Tanks and 3 Healers, Kali could be cleared by Cordelia, and so on.

I hope this doesn't become a trend.