I have two separate issues going on here.
I created a new character recently, and for some reason when using him, every single Archive run I get this boss at 1 - 4 - 3. Every time, without fail, 7 runs on the trot. Possibly bad RNG, but I've come to the conclusion he's going to be waiting for me every run, and I only have time for 2 runs a week, so I have to learn to deal with him or go back to using another character. If there's a way of shuffling bosses, I'd love to know what it is.
Second issue, the pillars pop up, he does his thing, I stand behind the pillars, sometimes I live, sometimes I die. I make sure the pillar is between me and the boss and I'm stood a bit of a distance back from it. It seems random whether or not I get blown up while standing behind the pillar. Is there another mechanic here I'm missing? Is it a case of I have to be in a precise line behind the pillar with very little wiggle room?
I've gone from consistently hitting top 20 on the leader board each week to not even getting on it because of this one boss, so any help appreciated.