The Luminoth D-Isl was one of the ten Keybearers sent to collect the Sky Temple Keys and is called "steadfast" by A-Kul. D-Isl was a victim of attempted Ing possession and self-terminated in Storage Cavern A of the Temple Grounds. Samus later recovers his key in the Ing Reliquary of the Sky Temple Grounds.
- "Steadfast D-Isl. Who shall disturb you among the trees of holy ground?" —Metroid Prime 2: Echoes Logbook "D-Isl's Key" (Metroid Prime 2: Echoes)
- "It is inside me. I feel it spreading, clawing at my will, tearing at my thoughts. It moves me against my will, to this cavern. Here it will end. I do not wish this, do not want my body to become a weapon for the Ing within me. It hates. It demands obedience. I will fight to the end. I shall self-terminate before I will be a pawn of a filthy Ing." —Metroid Prime 2: Echoes Logbook "D-Isl's Testament" (Metroid Prime 2: Echoes)