Jeffrey St. Croix (formerly known as Evil St. John) is Geoffrey St. John's evil counterpart from Moebius. St. Croix was a gang rival to Scourge the Hedgehog, and acted as a temporary leader to the Anti Freedom Fighters until he was arrested by the Zone Cops and became a loyal minion of King Maxx while in Zone Jail.
Evil St. John became the leader of the Anti Freedom Fighters after they abandoned Evil Sonic due to his bad leadership skills. However, the Anti Freedom Fighters later dumped Evil St. John for similar reasons after repeated defeats, and Princess Alicia Acorn became their new leader. (SSS: #10)
By unknown methods and means, Evil St. John was arrested by the Zone Cops and placed in Zone Jail some time later, where he became a henchman of the former ruler of Moebius, King Maxx. Following Scourge's idea of renaming Moebians so as not to be stuck in the shadow of Mobius, Maxx forced Evil St. John, along with all the other Moebians in prison, to rename himself- which he did, becoming "Jeffrey St. Croix". After Scourge arrived in Zone Jail, Maxx made a deal with him that as long as Scourge would not challenge his power in prison, Maxx's gang, Jeffrey included, would not kill him. (SU: #29)
After Scourge seemingly violated the deal with the arrival of the Destructix, Jeffrey, along with several thugs, escorted him to Maxx's cell. After Maxx gave the order to leave enough of Scourge to "be identified", Scourge retaliated in a panic by headbutting St. Croix and kicking the others. St. Croix and the others would have succeeded in killing him had it not been for the Destructix coming to his rescue, wherupon Jeffrey took another blow to the face from Sergeant Simian. (SU: #29)Afterwards, St. Croix eavesdropped on Fiona and Abby in the prison yard, taking interest when Fiona mentioned that she "always had a way out." Later still, while bullying Verti-Cal and Horizont-Al in the yard, he soon found himself being attacked by a much more confidence Scourge; he was "saved" by Fiona, who put on an appearance of keeping Scourge in-line. When Fiona, Scourge and the Destructix finally made their move, causing a massive prison riot, Jeffrey took the initiative and stole their confiscated belongings from the Prisoner Processing area before Fiona could recover them. Having heard Fiona in the yard earlier, Jeffrey realized that the riot was part of their "plan", and they had to have some means of escape. As King Maxx planned future conquests, Jeffrey dug through the Destructix's things while making his own plans, though not without catching some of Maxx's attention somewhat. As he tried to cover for himself, Jeffrey tossed aside the Warp Ring, which expanded into a portal, much to their surprise. However, before they could use it, the Destructix burst in, beating the two to a pulp and taking back their possessions. Jeffrey was presumably recaptured when the Zone Cops regained control of the prison. (SU: #30, #31, #32)
- It is possible that the way Jeffrey St. Croix is the opposite from Geoffry St. John is that he has remained loyal to his King, unlike Geoffrey. This would make him not unlike Anti Knuckles, who is a pacifist unlike Prime Knuckles.
- Jeffrey was the first character from Moebius to have been based on a character created for the comic series, rather than having previously been developed by Sega or for the Sonic the Hedgehog cartoon series.
- Jeffrey's first name is a homophone of that held by his Mobius Prime self. St. Croix is the name of an island in the Carribean.
Jeffrey St. Croix, as Evil St. John, was seedier-looking than his prime counterpart and had a spiky punk haircut along with a blue bow tie, black leather jacket and boots.
Following his imprisonment, St. Croix wears an orange jumpsuit with dark green boots. His hair became larger and more "suave", rather than the spiky haircut he used to display.