After the Manhattan Clan's awakening, Sevarius is given two assignments by David Xanatos as one of the head scientists at the Xanatos Enterprises subsidiary company, Gen-U-Tech. First, he was assigned to create a clone of Goliath, named Thailog. The second was to design an artificial gargoyle to work for Xanatos. This led to his creating the mutates.
Working with Xanatos, he mutates Derek Maza into Talon. While Goliath, Brooklyn, and Lexington rescue Maggie the Cat, Goliath knocks Sevarius into a tank full of electric eels, apparently killing him. This led to Talon's enmity toward the Manhattan Clan since Sevarius was the only one who could cure him.
The encounter was all but a ploy on Xanatos' end, however, as Sevarius had faked his death to continue working for Xanatos in secret. Goliath later kidnaps Sevarius, forcing him to create a cure for the mutates. When the mutates confront Goliath and Sevarius, Sevarius creates a "cure" suspected to actually be the poison that Maggie is almost tricked into drinking. Xanatos appears to rescue Sevarius, thereby revealing their true relationship. After Sevarius leaves with Xanatos, the mutates decide not to drink the cure out of caution and become allies with the Manhatten gargoyles.
Dr. Sevarius is next sent to Loch Ness in Scotland to study the Loch Ness Monsters. While there, he captures a female Loch Ness Monster. Soon after, when the Avalon travelers arrived, he captures Angela, whom he discovers was the biological daughter of Goliath after analyzing her. He attempts to capture the male Loch Ness Monster using a tracking device attached to the female and Angela. However, he winds up sinking to the bottom of Loch Ness in the sub, which was damaged by the Loch Ness Monsters.
Afterward, he works for Thailog and Demona's corporation, Nightstone Unlimited. He creates the clones of the Manhattan Clan, including Delilah, the mate for Thailog. Demona then assigns him to engineer a deadly carrier virus, the CV-1000, that she planned to release across the planet. However, she is stopped by the Manhattan Clan.
- Sevarius' name is misspelled as "Servarius" on his briefcase in the episode "The Cage".
- In the Goliath Chronicles episode "Genesis Undone", Sevarius mentions his full name as "Anton Bartholomew Sevarius." However, canonicity is debatable.
- The character of Sevarius bears many similarities to Severino Antinori, an embryologist who experimented with human cloning in real life. Series creator Greg Weisman has called this a "bizarre coincidence."
- Sevarius bares the same forename as Vincent Price's character in The Abominable Dr. Phibes movies. Fitting, given their megalomaniacal nature but vast ingenuity.
- Anton Sevarius at GargWiki