Following a battle with Atomic Skull, Mon-El was invited to join the new Justice League of America at the invitation of Doctor Light (Kimiyo Hoshi). After helping to save New Krypton and seeding the UP worlds in accordance with time-loop instructions from the Legion, Mon-El, now near death having become immune to the lead poisoning antidote, is returned to the recreated Phantom Zone by Superman and Chameleon, where he remains until rescued by the Legion in 1,000 years. Whether his long isolation has caused memory loss or he is carefully avoiding a time paradox by never mentioning his 21st century adventures is unknown. In the final issue of "War of the Supermen", it is revealed that Billi is pregnant, presumably with Mon-El's child.