Health, Global Mana, and Energy.
In the following text the word conduit refers to a champion that has been imbued with essence
Health is self explanatory.
Global Mana is mana specifically for the Sovereign, who can either cast things himself, or through people he gave his essence to (who are now his conduits). Spells cast with this should be considered to be cast by the Sovereign, but there should be ways to have these spells be changed slightly based on the skills of the conduits it was cast through (the champions that received essence). For example, a high INT conduit would increase the damage by a percentage, while a low INT one would decrease the damage. A high Wisdom conduit could decrease the cost of the spell, while a low WIS conduit would increase the cost. Other stats could add certain effects (conceivably a high STR conduit could increase damage boni given to units through enchantments).
Energy is a kind of mana specifically for units. Energy would be used to cast simple spells and to power special abilities. For example, a Priest would use some Energy to cast a healing spell, a vampire would use Energy to drain blood from an opponent, and a Berserker would use Energy to power up his 'Whirlwind' special ability.
Health regenerates out of combat, at a specific rate per turn, and can be healed both during and out of combat by special means (potions, heal spells, hospitals, etc.).
Global Mana only regenerates out of combat (modified by location of sovereign, special buildings, amount of controlled shrines, etc.).
Energy regenerates DURING combat, at a set rate (changes depending on unit load-out), and fully regenerates upon leaving combat.