Health Regeneration + Spell Drain + Movement Speed = Preservation
Each spell will add a stack of 'Preservation' to you. 'Preservation' will increase your HP-Reg by +0.2 * (1 + Movement Speed Value). If you drop under 35% health 'Preservation' stacks will be consumed each second and you will be healed by 10 * (1 + (Spell Drain Value * 10)) per stack.
Maximum stacks: 20. Maximum Health Regeneration: +4 * (1 + Movement Speed Value).
Movement Speed improves the regeneration amount and Spell Drain improves the heal amount.