hybrid cargo
Tooltip on Grenade says it cost 50 mana at level 5, tooltip on skill bar at bottom list 60 mana while in town, using it did consume 60 mana. I do not know if it has different cost from tool tip at different levels or not, as I do not have resources to spare to test for that.
When starting a round with Blessing of Prowess which reduces by 25% it does correctly lower to 45 mana cost from the 60 it was though.
stiff cove