User blog comment:SirAston/URF and the LoL Engine - A To-Do List/@comment-6301771-20140402151438/@comment-24030368-20140402200134

@Airclever Well Swain's ult uses mana, what, once-twice a second? I imagine that if one of those instances uses more than your mana pool it will deactivate, not the total consumption over time. If that makes sense.