Is there some aspect of this or the math behind it that I do not understand? If it reduces the damage that you take, that is good, right? Or does it only reduce damage to me if I would otherwise get a mortal attack against me?
It reduces damage to you based on the level of the ring and your current missing HP. The effect is mediocre unless either: the ring is high level (5 or 6+) or you’re missing a lot of HP. Even then you need the ring at +8 if you want ~50% damage reduction at 50% HP. Compared to just about any other option upgrading tenacity is a poor choice.
Edit: A while back I graphed tenacity and a bunch of other scaling effects to better understand how they scale with upgrades, here’s +0 -> +4 and +8:
You can see that the scaling itself isn’t terrible (the effect is actually pretty good at high levels) but the effect is pretty mediocre at the levels you’ll encounter most often (+0 -> +2.) To get a solidly good effect out of the ring you need to live in the danger zone at fairly low HP, which puts you at risk of getting instagibbed by a surprise attack.
I don’t really like the trade offs Tenacity requires but if I were going to play a tenacity dump game I’d be targeting damage reduction equal to missing HP for a given target and then try to stay as close to that level as possible. 50% DR at 50% HP happens at +8, and 70% DR @ 70% missing HP happens at about +9/+10. I’d probably go for +10 then try to stay right at ~30% total HP. The problem is that you’re devoting 2/3 (or all with the runes challenge) of your offensive upgrades to just soaking damage and that leaves you with really mediocre damage output.
But even with upgrades and at low health, it will never reduce damage under 1 hp, so you’ll always take damage… Which isn’t a good combo when at 1 hp. That’s why this ring is a very bad idea. Unless you are going with Faith Is My Armor, you could just do yourself a favor and dump those upgrades into your armor; which will reduce the damage that you take to 0 hp; and you can stay at high levels of health for your armor to be effective.
Yeah, I think we’re saying the same thing here. The loss of other utility just doesn’t make upgrade dumping tenacity very worthwhile and at the levels you’re most likely to encounter the effect without dumping it’s just not good enough to justify using when you can slot literally anything else.
I guess it could be fun on the right kind of berserker build but that’s about all I can come up with.
