Simon was a member of the Dark Legion and the foster father of Julie-Su and husband of Floren-Ca. During his life time, he was sent on numerous missions with ill-equipped troops by Kragok hoping he would be killed, though each time he managed to survive. Years later after reuniting with Julie-Su, he was captured and held prisoner with his wife on the Dark Legion's Battle Cruiser. Once freed, the current Guardian, Knuckles the Echidna, managed to pull some strings and get them an apartment and Simon and Floren-Ca attended his funeral. The following year he was later killed, becoming one of the many victims of Dr. Eggman's Egg Grape Chambers.
Julie-Su's Surrogate Father
Simon took Julie-Su into his care after her memory was erased following the death of her mother Mari-Su and disappearance of her father Luger. Before that, they watched Julie-Su growing up as a toddler, being shunned and ignored by her half-brother and half-sister. It made them very sad about it. Both he and his wife were warned not to tell Julie-Su of her origins by the new Dark Legion Grandmaster and Julie-Su's half brother Kragok. Later, Kragok and Lien-Da schemed on a means to get rid of Simon. Because he worked directly for Moritori Rex as his aid, simply having him assassinated was not an option. Thus, then dispatched him with a poorly-equipped detachment of troops on a mission, but Simon managed to survive. Julie-Su was taken away from Simon and Floren-Ca when she was thirteen, where she became a member of the Dark Legion. (SSS: #11)
Simon later reunited with Julie-Su while she was searching the old ruins of the Dark Legion's base on Angel Island. Upon discovering him, Simon told her of her past and her memories which had been wiped away by her half-siblings. The two left the base together hoping to rebuild their family. (SSS: #11)
He was later captured along with Floren-Ca and Julie-Su by the Dark Legion and brought on board the Battle Cruiser as prisoners before the Quantum Beam was fired. While imprisoned, Julie-Su mentioned how she felt she couldn't stand being locked up much longer. Simon replied things could be much worse, and that the Dark Legion "aren't renowned for their hospitality". The conversation was broken up when Lien-Da came in and brought Julie-Su to the bridge. The three were later set free after Knuckles agreed to work with the Dark Legion. (StH: #100, SSS: #14)
Knuckles managed to pull some strings within Echidnaopolis and find an apartment for Simon, Floren-Ca and Julie-Su, once Dimitri had begun open discussions with the High Council of Echidnaopolis to reunify their people. Simon told Knuckles it was a kind yet unnecessary jesture as he and his wife would have been comfortable remaining on the Battle Cruiser, though Knuckles responded saying it was unlikely given that Dimitri's health began to fail and the Legion would likely not last after his death. (StH: #114)
PersonalityUnlike most Dark Legionnaires portrayed, Simon is shown to be rather nonviolent and kindly, particularly towards Julie-Su. His affection towards her is such that he was willing to leave the Dark Legion, risking severe punishment for betrayal. (SSS: #11)
The fact he was trusted to care for the Grandmaster's daughter and that Lien-Da and Kragok were unwilling to outright get rid of him suggest he was a high ranking or well respected member of the legion.