The Warden Eternal generally serves to uphold the principles of the Forerunner and shows strong contempt for both Blue Team and Fireteam Osiris. In the case of Blue Team he expresses confusion about why Cortana places value upon the Master Chief and makes every effort to prevent Blue Team from removing Cortana from the Forerunner world of Genesis, even when Cortana actively fights against him. Although he is a single psychological entity, the Warden has multiple bodies which allows him to repeatedly return to face his human adversaries, although he is defeated by them every time.
The Warden Eternal is far larger than the player characters in the game and is capable of moving quickly towards targets. Using his blade he is capable of a melee attack that depletes a character's health and shields in a single blow. He also possesses two projectile attacks: A fast explosive projectile and a slower moving projectile that like is melee attack is capable of downing a character in one hit. The Warden can be hindered by being shot in the head, while his weak spot is on his back.