Sub-Bosses, also known as Underbosses or Dark Egg Legion (D.E.L.) Grandmasters were beings originally employed by Dr. Ivo Robotnik to watch over various territories across Mobius he controlled to enforce his will, and to annihilate opposing forces threatening his empire. After his death, Dr. Eggman employed old and new Sub-Bosses to serve his own dictatorship.
Formerly, Sub-Bosses were known to have been located in Angel Island, Sand Blast City, the Dragon Kingdom, the Great Canyon, and the Kingdom of Mercia. All of these Sub-Bosses were subsequently defeated or destroyed by the local resistance, sometimes with help from the Knothole Freedom Fighters. (StH: #58, #138, #181, KtE: #12, TMS: #1, #3, STT)
As of 3237, the Eggman Empire had various Sub-Bosses stationed at Flicky Isle, Station Square, the Land of a Million Lights, Southern Tundra, Downunda, and the Mobian Sea. However, due to the decline of Dr. Eggman's sanity as well as the Chaotix's destruction of New Megaopolis's communications center, the various Sub-Bosses went unchecked as Dr. Eggman obsessed over defeating Sonic the Hedgehog, effectively ruling their own personal fiefdoms. After adding the former Dark Legion to his cyborg Mobian armies, Eggman renamed the various groups the "Dark Egg Legion", and most of his Sub-Bosses were renamed Grandmasters. (StH: #190, #194, #214)
- Iron Queen (Former Dragon Kingdom Sub-Boss)
- Scorpius (Destroyed)
- Iron King (Location unknown)
- Crocbot (Destroyed)
- Hugo Brass (Demoted)
- High Sheriff (Deceased)
- Lien-Da (Trapped in another Zone)
- In one of his Q&A sections, Ian Flynn stated that all active Sub-Bosses (with the exception of the Iron King and Queen) would now be titled "Grandmasters", going off the Dark Egg Legion formula. (1) However, the title Sub-Boss was shown to apply afterwards.
- According to info released in the fifth volume of the Sonic Universe Graphic Novel Series, Battlekukku XV was originally considered as a candidate for Sub-Boss of the Land of a Million Lights.
- Abandoned story concepts that take place after Sonic's return from space included Jack Rabbit and Croctobot as Sub-Bosses under Eggman in the Great Desert and Downunda, respectively. Gala-Na would also have been a Sub-Boss. A new character named Colonel Mange would have been the leader of the Dingoes and Sub-Boss of Angel Island. 2