Well, Superman or not, I don't see any other option. If Arcane's castle is as well-guarded as Frankenstein says, maybe this mystery prisoner is the key. 
Animal Man (Volume 2) #15 is an issue of the series Animal Man (Volume 2) with a cover date of February, 2013. It was published on December 5, 2012.
Synopsis for "Rotworld: The Red Kingdom, Part Three"
The remains of Central City have been claimed by the gorillas of Gorilla City. Led by Grodd, Mallah and the Brain, the gorilla army soon overcomes Buddy Baker and his band of heroes connected to or protected by The Red - and John Constantine. They are saved, fortunately, by the arrival of Frankenstein and his Patchwork Army.
With Frankenstein's help, they defeat the gorillas, leaving a few alive to spread word of their defeat. Impressed, Buddy asks Frankenstein to join them in their quest to take the Kingdom of The Rot and bring down Anton Arcane once and for all. Frankenstein warns that such a venture would be difficult - more difficult than this battle with the gorillas. He has done his own part by creating an army of patchwork people who are immune to the Rot - though most would not choose such a life. To build their strength, Frankenstein suggests that they follow up on a rumour he has heard about a prisoner Arcane has trapped beneath Metropolis - one too powerful to be turned or destroyed by Rot. Perhaps this prisoner could be a helpful ally to them. They speculate that the prisoner may be Superman, but decide that they should investigate whether it is or not.
A year ago, Maxine Baker had taken shelter in a diner with her cat Socks when they encountered William Arcane. Despite Socks' warnings that it was a trap, Maxine insisted on hearing William's claims that he had reformed since his encounter with Swamp Thing and his half-sister Abby. He claimed that he could use his connection to the Rot to remove its effects from people, and that he had already done so for Maxine's family. When Maxine followed him to be reunited with them, she discovered that he had betrayed her, and the Hunters Two were waiting there for her.
While asleep in the caravan headed for Metropolis, Buddy dreams of waking up in his house at San Diego, his family intact. Young Maxine drags him out of bed for his coffee, but his wife Ellen is strangely quiet when he asks where his son Cliff is. Maxine reveals that Cliff is in the backyard, and Buddy is disturbed to see Cliff lying in the back yard, wearing an Animal Man costume and infected by the Rot. Cliff cryptically warns Buddy not to turn his back on the boy, because he won't be dead yet. Buddy doesn't understand, and wakes in a sweat. By the time he is awake, they have arrived in the ruined city of Metropolis.
Remarkably, the city seems to have been overtaken by vines of The Green. This is strange, given that it is apparently a prison of the Rot. Regardless of the strange familiarity of the power in Metropolis, Buddy insists that they must find this underground prison, and suggests that they find their way into the old subway system. While Buddy and his companions head out, Frankenstein and his army stay behind as sentries.
Using his animal abilities, Beast Boy transforms into a bloodhound and sniffs out the subway entrance. Begrudgingly, John Constantine agrees to go first. Steel begins to pick up a faint, but familiar energy signature - but it is not one of any known super-human. The subway system is overrun with the thick and healthy vines of the Green, making it clear that they are on the right path to this prison.
They are surprised when they cut through the bars and find a Green Lantern trapped there.
Appearing in "Rotworld: The Red Kingdom, Part Three"
Featured Characters:
Supporting Characters:
- Maxine Baker (Flashback only)
- Socks (Flashback only)
- Black Orchid
- Beast Boy
- Steel
- John Constantine
- Patchwork Army
Antagonists:
- William Arcane (Flashback only)
- Hunters Two (Flashback only)
- Gorillas
- Brain (Dies)
Other Characters:
- Medphyll
- Mary Frazier (Rotten) (Flashback only)
- Ellen Baker (Rotten) (Flashback only)
- Cliff Baker (Rotten) (Flashback only)
Locations:
- New Gorilla City
- San Diego (In dream sequence only)
- Metropolis
- Daily Planet (Destroyed)
- Louisiana (Flashback only)
Concepts:
Items:
Vehicles:
See Also