From Destinypedia, the Destiny wiki
The Sentinel is a Void-based Titan subclass that is available in Destiny 2. It gains access to a Void shield that can be used in close quarters and as a thrown projectile. The Ward of Dawn from its predecessor, the Defender, can also be used with the appropriate subclass tree.
Set 1 - Grenades
Set 2 - Movement
Set 3 - Super
Set 4 - Class Abilities
Set 5 - Subclass Tree 1: Code of the Protector
As the name suggests, Code of the Protector is oriented primarily towards providing protection for oneself and allies. Its abilities focus primarily around being able to take more damage.
Set 6 - Subclass Tree 2: Code of the Aggressor
Code of the Aggressor is self-explanatory, in that it focuses primarily on aggressive use of abilities.
Set 7 - Subclass Tree 3: Code of the Commander
Code of the Commander provides a mix of the supportive and aggressive gameplay seen in the other two trees. The main mechanic, void detonators, are especially effective when paired with Magnetic Grenades.
List of appearances