Granblue Fantasy グラブル – Unite and Fight NM90 Tsukuyomi 光有利古戦場90HELL ツクヨミ − アフィリエイト動画まとめ
the boss seems to be focused on debuffs at least in this first version NM90. I'd suggest to bring clarity or some character with a similar skill because Shadowed can be pretty nasty to your damage output.
Curious to see if they'll change the number of debuffs in the NM95/100 versions…