Specifically Lord Stormsong.
He is one of the two boss encounters that drop a BOP cloth ensemble set (Tidesage).
By now, most BFA dungeon encounters are trivial at ilvl ~200, but there are still some mechanics which completely prevent the player from defeating them.
Namely the mind control, which comes in ten seconds after the pull and causes the boss to despawn and reset. While there are some workarounds, it is still highly gear dependant because you in most cases won’t kill in time before second one hits.
I found some success with my demonology warlock but it’s an completely unnecessary hassle each time. Send Felguard at him and spend next 10 minutes on the other end of the cathedral semi afk hoping that you get lucky with RNG and that he kills the boss for you.
The embalmer boss in King’s Rest already received similar treatment so you don’t get locked inside of the coffin with no one to help you.