User blog comment:Lesanthosxia/Grugnir, Guardian of Immortality/@comment-4636093-20120129205753/@comment-2066615-20120130133634

It was originally 10 as base, and 100 when at 10% or lower life at all level (Due to armor and Mres can also interpret as a form of "effective health"). I'm thinking of making improvements per level instead of a flat out bonus, but then the numbers would be tricky.