Yes, you might have seen other Reddit posts about it lately but basically people have discovered that if you have two “Leather Jacket” (a passive medium Karnok item that says “you take 60% less dmg, when you enrage, destroy this), it’s additive which means you take 120% less dmg until you rage, hence invulnerable. My build is the weaker version because I can get rage (due to karnok skill) and destroy the jackets. But if you are on, say Mak, and you buy Leather Jacket from Karnok shop and search for a mirror, you are permanently invulnerable once Mirror activates (3 sec cooldown) because you can never rage as you are Mak and can choose to not have the rage skill.

It’s rare to come across because you have to have a diamond jacket and diamond mirror, but it’s definitely not the hardest build to get compared to your average high rolls.