Test of Mettle

The first Test is IMPOSSIBLE to beat with chaos build or the rare spawn is glitched...can't get it past 90% below HP...it instantly regens...it only has break armor and elemental resistances...chaos should melt it, doesn't ZERO damage to it none...zip zilch NADA...

Its impossible to beat...will either need help or have to respec my entire build to proceed with the game

You can't just say it's impossible without showing your build, items and other things so we can have a look and come up with advices.

Yeah, I don't know what is happening with this rare. I've tried resetting to change its mods, but he just regens to full in like 2 seconds no matter what he has on him. I'm playing fireball + firestorm and my damage is pretty good everywhere, but I can't out DPS his heal... Fire damage too BTW, not chaos so IDT it's just chaos damage that's the problem.

I had the same problem, boss was totally immune against 99.9% of my attacks so I made a Blasphemy skill gem and put Ritualistic Curse as support and with some luck I got it to work and killed him. But he still heals REALLY fast if you let him. This will hopefully be patched in next patch.

I am presently running into this issue right now with a fire turned chaos build. The boss just heals whatever i throw at him. I have tried to reset, and its the same, just with different rare modifier on it, the rare enemy in the Kaom's Test of Mettle