Upon dropping below 50% maximum health, you are healed for「 30% of your maximum health 」「 2.5% of your maximum health every 0.25 seconds 」over 3 seconds (45 second cooldown, reset upon death).
This augment page for Dawnbringer's Resolve reflects public Arena Mayhem data for patch 26.19.
Graded against the other augments of its rarity, from all champions' games. The source publishes no per-champion results for augments.
See the Gold tier list