Daniel Radford was a member of the original Zodiac gathered by Taurus (Cornelius van Lunt).
Leo was one of the Life Model Decoy (LMD) team of androids known as the Zodiac created by Scorpio to serve him. Scorpio was forced to activate the Zodiac prematurely when he was attacked by the Defenders and Leo attacked Hellcat, badly wounding her. He was defeated, however, when the Zodiac member known as Gemini turned against the rest of the Zodiac and turned on the device meant to kill the Moon Knight while Leo was inside.
Leo survived and later, along with the other Zodiac members, joined forces with the Avenger Quicksilver against his former teammates the Avengers during a period when Quicksilver was mentally unstable. As part of one faction of the group, Leo fought the West Coast Avengers with Quicksilver at the circus where the Avengers had first formed. After freeing the circus' lions to wreak havoc, Leo fought the Avenger Tigra, who was struggling with the feline side of her personality at the time, and so found it difficult fighting him. Her teammate Wonder Man took over fighting Leo, and overpowered him. The Zodiac were once again defeated and Leo was turned over to the authorities by the Avengers.
Later, Leo was set free from prison and joined the Zodiac once again and they confronted the human Zodiac Cartel, which they were patterned on, in Dallas, Texas. The LMD Zodiac succeeded in killing all of the human Zodiac members with the exception of Cornelius van Lunt and took their places in the criminal underworld.
Leo is a member of the villainous organization known as Zodiac. He first appeared with the team when they attacked Department H in a successful attempt to steal an Nth Projector.
K'Beer Okoye was a member of the Zodiac as Leo. They battled the New Warriors.
Leo and the rest of the Zodiac were decapitated by a one man Zodiac who wanted to free up the name for himself.
Leo was one of the members of the new Zodiac team, a group of ambitious people who wanted to conquer the World using special suits, which gives super-powers, supplied by Thanos, who wanted them to steal different powerful items and take them out from Earth in order to bring balance to the planet and the cosmos.
He was one of the Zodiac members who attacked the Helicarrier in order to retrieve an Ultimate Nullifier, while battling the Hulk, he suffered a heart attack and died, the energy of his suit passed through Iron Man's armor, which helped him to known where did the Zodiac have their powers from and shut them down, but Thanos appeared.
Avengers:United They Stand
Leo (alongside the other Zodiac members) appears in The Avengers: United They Stand. He is depicted as a lion-like alien.
Leo is featured in the Ultimate Spider-Man episode "For Your Eyes Only." The foot soldiers of Leo are depicted as wearing lion masks.