Sirus has some design issues.

So I generally do fine on Sirus, this time I died in his final stage, fine. So I come back and as I enter the arena "DIE!" before I can even see him or tell where he is at I get one shot through 5 endurance charges and 5.2k and molten shell. Alright fine, that was stupid. Come back, same thing. This happened four times total, if I was a new player that would be absolutely demoralizing. How can you justify that or even counter it? After the first time I started just leap slamming in a random direction, but because of rubber banding that didn't do much. The fight was originally too easy, I agree with that, but having a mechanic you can't counter or see that can one shot through that much mitigation seems unreal. Developers what am I missing, when you clear A8 Sirus and die in last stage how do you personally deal with this?

I could beat him last league up to halfway thru they patched and performance went to crap. This league I can't beat him on Awekening zero. I beat all concuerurs every map boss on horrible mods deathless but cant get thru spinning laser phase. I think if i get something for resisting the slow or whatever i could, but regardless what a garbage encounter and I honestly think u nailed it. New player will bolt.

I dunno they need to cut the bullshit area denial stuff the mechanics just arent there. Be an arpg its a clunky game it just honestly is bad design. I dont think player enjoyment matters just retention, they feel the more you fail the more you'll play or want to copy top players. But top players dont really engage mechanics they do everything to build to ignore the mechanics.Like I want to beat fight mechanicaly but i'm now just gna build to ignore last phase or quit til next league.

The encounter obviously has death detection and proximity detection, else how would he spawn an extra storm on death or start casting (and the screen zooms out) on proximity.
There are several builds that need to prepare before combat (summon, recharge, etc) so having him do abilities whilst out of range after death is bad.
During the first three phases he goes 'inert' after deaths, he should do in the final phase as well until you approach him.

As an additional note, bit OT, why oh why does he always wander off 'north' towards the bloody stairs if you die? this is not the only clear area for him to have fun in whilst I prepare to engage him again.