The Luminoth S-Jrs was one of the ten Keybearers sent to collect the Sky Temple Keys. He is called "loyal" by A-Kul. He was one of the last of the cadres to fall and was sent back to Aether by A-Kul for reinforcements, but he was followed and slain by the Ing. He died in the Sanctuary Entrance of Sanctuary Fortress. Samus later recovers his key in the Hive Entrance of the Ing Hive.
- "Loyal S-Jrs. He no longer breathes, looking down at the great bridge of a holy fortress." —Metroid Prime 2: Echoes Logbook "S-Jrs's Key" (Metroid Prime 2: Echoes)
- "A-Kul tried to send me back to Aether, that I might get reinforcements. Both cadres have been attacked, devastated. The Ing followed me. They came, wearing the skin of beasts. I gave them a good fight, yet, I have failed. May I redeem my honor in the next life. Here, at the fortress entrance, I breathe my last." —Metroid Prime 2: Echoes Logbook "S-Jrs's Testament" (Metroid Prime 2: Echoes)