This system is based off of Dungeon Defenders, where there was only one type of mana, and that mana would be used to both activate abilities and build towers.
Blue mana (also known as "Ability Mana") is used to activate hero abilities. It regenerates passively during the Combat Phase, albeit slowly. It also completely regenerates at the start of each new combat phase. mana doesn't disappear between rounds. The values for blue mana's regeneration rate are currently unstudied. Blue mana is set to 250 and can only be improved from ascension and from shards
For some characters it works a bit differentially name/gain eg Series EV2 is replaced with heat when maxed stops all ability usage until reaching 0 by shooting main weapon, and the barbarian has two ability power pools fury/wrath which are filled by attacking enemies.
Green Mana (also known as "Building Mana") is used to Build/Repair/Upgrade defenses. It is obtained exclusively from defeated Enemies and Mana Nodes. Unlike Blue Mana, Green Mana does not regenerate and does not refill at the start of a combat phase. There is no reasonable limit to the amount that can be held.