Dark Agon Temple Key 3 is the final Dark Temple Key required for access to the Dark Agon Temple in Metroid Prime 2: Echoes. It is located in the Battleground. Upon entrance, it would appear that the Key is safely located in a Safe Zone, though when Samus approaches it, six Warrior Ing will challenge her for it, taking it until she kills all of them. Strangely, an Ing in liquid form will release it back into the Safe Zone even after all Ing are killed. The Key of J-Stl is also located in Battleground.