Mad Hatter (Jerome Valeska)

Mad Hatter is an alias undertaken by Jerome Valeska after he was implanted with a new persona by Professor Hugo Strange after being resurrected at Indian Hill underneath Arkham Asylum. He later became an enemy of Jervis Tetch, who he himself was infatuated with the character Mad Hatter.

Background
Jerome Valeska was the son of Lila Valeska and Paul Cicero, two employees of Haly's Circus. Jerome was unaware that Paul was his father, with his mother claiming that his father was a captain who died at sea. It is implied heavily in his youth that Jerome was abused by his mother and boyfriends whom she slept with, and he soon started growing into an unstable one man, although he managed to hide his true, manic behaviour as a decent, ordinary young man. But this all changed when at the age of 19 he butchered his mother to death with axe, having had enough with her acting like a "whore". Cincero helped him cover up the crime, but Jerome was later caught out by Detective James Gordon and sent to Arkham Asylum.

A couple of months later Jerome was broken out of Arkham by Theo Galavan along with a few other inmates and tasked with heading a group known as "The Maniax" to strike chaos and terror into Gotham City. This climaxed when Jerome was murdered by Galavan during a charity event for the Gotham City Children's Hospital, as it turned out Galavan only used Jerome as a pawn to make himself look like a hero to the city as part of a bigger scheme.

Jerome's body came under the possession of Professor Hugo Strange and was preserved in a glass tube along with other corpses at the Indian Hill facility underneath Arkham Asylum. A few months later, Strange discovered a way to resurrect the dead, with the first successful candidate being Theo Galavan himself.

Implanted persona
Jerome ended up being resurrected by Strange, but like the previous subjects his mind was fractured and he didn't remember much of his past (apart from tiny details). The resurrection process and mutation to his body granted Jerome with the ability to regenerate health and heal wounds. Strange gave Jerome the persona of "The Hatter" from Lewis Carroll's fantasy novel Alice's Adventures in Wonderland.

When the Court of Owls ordered Strange to move his subjects to a facility upstate, Jerome was packed onto a bus along with the other Indian Hill inmates. But this plan was foiled after a resurrected Fish Mooney hijacked the bus, and ended up crashing it into Gotham. Jerome along with the other inmates were released by a well-meaning homeless woman, who was shocked at the sight of the monstrous passengers. As Jerome made his way into the city, he let out his trademark laugh.

The Amazing Hatter

 * To be added