The original "non-team", the Defenders began as an informal alliance between Doctor Strange, Namor, and the Incredible Hulk. As more members were added, the Defenders eventually became a regular team of heroes. Their strongest ties to the X-Men came during the New Defenders #125-152, where Beast, Iceman and Angel were all regular members of the team. When every other active member was killed battling the Dragon of the Moon, the X-trio was free to reunite with Cyclops and Marvel Girl to form X-Factor.