Untiring

1.5% of Physical Damage prevented from Hits in the past
10 seconds is Regenerated as Life per second
40% increased Life Regeneration rate
[1]

Untiring is a notable Ascendancy passive skill for the Juggernaut that grants life regeneration and grants bonus life regeneration based on the amount of physical damage that was mitigated from hits.

Mechanics

The prevented damage is the difference between the calculated damage before mitigation and the damage taken after all steps of mitigation if that difference is positive, including not just physical damage reduction and Armour but also Block and Spell Suppression.^[1] If the user takes more damage than the amount calculated before mitigation, it will not count as "negative" prevented damage.^[2] Physical damage taken as another damage type will not be considered prevented physical damage.

The keystone Divine Shield uses the same wording to regenerate energy shield instead.

Petrified BloodPetrified BloodSpell
Level: (1-20)
Reservation: 35% Mana
Cooldown Time: 1.00 sec
Can Store 1 Use(s)
Cast Time: InstantRequires Level 24Applies a buff that protects the lower half of your life, preventing some of the immediate life loss when damaged by hits and applying the loss over time instead. Your life cannot be raised above low life other than by flasks, and while above low life, skills will cost life as well as mana.Life Recovery other than Flasks cannot Recover Life to above Low Life
When taking Damage from Hits, 40% of Life loss below half Life is Prevented, then (100-81)% of Life loss prevented this way is lost over 4 seconds
Skills gain a Base Life Cost equal to 40% of Base Mana Cost while not on Low Life

Additional Effects From 1-20% Quality:
-(0.25-5)% of Life loss prevented is lost over 4 secondsPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. and SteelskinSteelskinSpell, Duration, Guard
Level: (1-20)
Cost: (4-16) Mana
Cooldown Time: 3.00 sec
Can Store 1 Use(s)
Cast Time: InstantRequires Level 4Applies a buff which can take some of the damage from hits for you before being depleted. Shares a cooldown with other Guard skills.Base duration is 1.50 seconds
This Skill's Cooldown does not recover during its effect
Buff grants Immunity to Bleeding
70% of Damage from Hits is taken from the Buff before Life or Energy Shield
Buff can take (54-2209) Damage

Additional Effects From 1-20% Quality:
(0.5-10)% increased Cooldown Recovery RatePlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. do not count as they do not affect the amount of damage taken, but instead change what and how much you lose as a result of taking the damage, and therefore do not contribute to "prevented damage".^[3]^[4]