I think it was Zantarin. He was a red namedw boss at SR24 and 4th phase. I was playing SEP’s Warden with max resists and overcapped by 50% on all resists and right around 28k health. I have been facetanking every single mob up to that point without an issue.
I cleared 2 of the other bosses and as I was running up to Zantarin, before I could even attack, he did an attack and I went from full health to dead in 1 shot. There was no reduction in health bar, I simply went from full health to 0 instantly.
What the hell was it and how do I avoid it next time?
He has shotgun attacks Grim Dawn Monster Database
Shotguns do be like that, especially when you’re debuffed.
Either avoid such shotguns (know animations / when he does them / wait for them / bait them).
and/or accompanying debuffs
or have tankier character - for example some Retal Warder with a Shield and Obelisk of Menhir.
Flat Absorption (Obelisk, Ascension, Inquisitor Seal, Phoenix) works well against shotguns.
If I remember correctly, he will not use this attack if you’re close to him.
So the real danger is at the beginning, as you close up the distance. He will use this attack when he raises his book, while you’re a few meters away. You need to dodge that attack. Then it’s just bonk-bonk-bonk ded.
If his aggro has been activated, zigzag or move in circle to his face. If his aggro hasn’t been activated, big chance if you get close fast enough (using SS, Blitz etc. but not VM or charge rune) he only auto attack you instead of using the shotgun attack. Usually moving normally towards him activates both his aggro and shotgun attack, retreating or attacking from range also trigger his shotgun attack.