You can 1 phase him with a timed combo by all 3 players using whither, dark drinker and an oppressive darkness. Even if it's a 2 or 3 it's still fast. Lake of shadows with momentum solar speedruns too. Goodluck.

I do this. But I wish Contact gave the upgrade material. I actual like the new event but you get crap for completing it. I will say, I get dirty engrams all the time from doing anything in the game.