(セルクス Serukusu?) is a Voxai. He was one of the "Overmind's elite protectors", and probably one of the few who willingly supported their despotic ambitions. He confronted Thebes at the entrance to Colony Alpha's teleport gate. After being knocked out by Sonic's group, Sonic was given one of the two Great Emeralds and Thebes extracted the teleport code from Thelxe's mind and imprinted it on Sonic's. Thebes stayed behind on Colony Beta, to "keep his mind on" Thelxe.
- Thelxe is presumably named after Thelxiepeia, one of the named sirens in Greek mythology. The three members of the Overmind whom Thelxe served were also named after sirens.
|Sonic Chronicles: The Dark Brotherhood|
|Playable characters||Sonic | Tails | Amy | Knuckles | Rouge | Big and Froggy | Cream and Cheese | Eggman | Shadow | Omega | Shade | Super Sonic|
|Other characters||G.U.N. | Commander | Nocturnus Clan | Ix | Nestor | Super Ix | Gizoids | Emerl | Scylla | Charyb | Knuckles Clan | Egg Bot | Swatbot | Krag | Syrax | Raxos | Haniman | Queen N'rrgal | Thebes | Thelxe | Overmind | Twilight Cage Pirates | Precursors | Chao | Argus | Vector|
|Places||Green Hill Zone | Central City | Blue Ridge Zone | Mystic Ruins | Angel Island | Metropolis | Metropolis Ground Zero | Kron Colony | Twilight Cage | Zoah Colony | N'rrgal Colony | Voxai Colony Alpha | Voxai Colony Beta | Nocturne|
|Other||Dexter | Argus event | Sequel | Archie Prequel|