Spirit: A new resource called Spirit is added in addition to Life and Mana. Spirit is used to reserve skills with persistent effects like buffs and auras, upkeep permanent minions, and enable trigger meta gems. Spirit can be increased through story boss rewards, modifiers, and sceptres.
Killing normal rarity monsters no longer grants flask charges.
Defeating optional story Bosses can grant items that grant permanent attributes and Spirit bonuses. These upgrades are character-specific. Larger bosses are more mobile because they can have multiple hitboxes, unlike the limit of 1 in POE1.