Learn Path of Exile: Sentinel New Content Path of Exile’s latest expansion, Sentinel, is now available on PC and macOS. The expansion kicks off a new Challenge League in the free-to-play PC game, with the core mechanic being customizable sentry balls that follow the player to fire beams of magic at enemies. But Sentinel isn’t meant to make players’ lives easier — quite the opposite, in fact. Their Chaos Orb...