
I was playing a halfling skirmisher, level 25, in nightmare/roguelike (didn't manage to win in nightmare yet

In Daikara, just before level 20, I had found almost at the same time the burning star and an escort who teached me Track. From this point onward I played slower, mapped everything and understood just how powerful this was.

At level 21 I found the Untouchable. I was already seeing the rest of the west being a breeze with this wonderful armor and the rest of my stuff being very good already (60%+ resist in confusion and stun among other things).
Then I went to Celia's crypt and that's when it happened.

I open a coffin and this Bone Giant pops up. I look at it a bit, see nothing that I can't handle. I use Bash and Smash to put up a little distance and that's when the shit hit the fan.
I push him back and my projectile is in the air, waiting. He uses blast which deals me 331 of my ~700 HP and the Untouchable decided not to activate a shield for reasons I don't get.
The blast pushes me directly into my projectile from bash and smash. Trained reactions (level 5 of course) activates and reduced the damage by about 15-20%, can't remember the exact percentage it had, but still no signs of the Untouchable.

And of course I had gotten a crit. And I still get 467 damage from myself. Causing me to die with approximately -30hp.

And that concludes my most frustrating death of the year, thanks for reading all this, and if you have any idea of how I could have avoided that don't hesitate to say so. I'll feel better if it was clear it was my screw up and not the game decided I had too many nice things in this run.

Silver lining : yay! I got a new achievement!