User blog comment:Caporai/Gideon the Legion/@comment-5208038-20120801223342/@comment-3286233-20120801224701

Temporarly.

let's say he got 1000/1000 mana. When he uses his R, he will gain "400" mana, while he depletes his mana down to 750, meaning he have now 750/1400 on his mana while his R is active. At the end of duration, 1400 will go back to 1000