The ESO Companion System
is part of the Blackwood Chapter that will launch later this year in June. The ESO Companion System lets you unlock companions through quests. Companions can fight alongside you in combat and provide utility and support for you while you explore Tamriel.
Once you have a companion unlocked you can level the companion up to make him/her even more powerful. There is also a full dialog system attached to each companion in ESO. You can also equip them with gear and slot individual skills. The Companion combat behavior can be set to either be a full healer or damage dealer or a mix of both, whatever you pick!