League of Legends Reforged Rune: Presence of Mind

Scoring a takedown against an enemy champion restores 15% of your maximum mana or 15% of your maximum energy after a 1-second delay.

Damaging an enemy champion restores [6−50 for Melee | 4.8−40 for Ranged] mana or 6 energy (depending on level) (8 second cooldown).