Ink was one of the members of the Young X-Men team that believed themselves to have been organized by Cyclops. He was a loud-mouthed, rude teenager who didn't care what others thought about him, as proven by when he stood up to two police officers who wished to arrest him in a tattoo parlor. He fought back using his bio-hazard tattoo, which produced the same effects as a biochemical weapon, making the police officer instantly very sick. Despite this, he was arrested anyway.
While sitting in jail and waiting to rot, Eric sassed a guard who ended up freeing him. As they were leaving, the guard turned off an image inducer and revealed himself as Cyclops.
Cyclops gathered Eric along with the other members of his new team into the New X-Men's former training simulator, the Danger Cave, built by Prodigy. There he trained them to take on their first mission, to take down the latest incarnation of the Brotherhood of Mutants, which consisted of the former New Mutants.
Ink and Blindfold were assigned to the Blue team and were sent to apprehend Dani Moonstar. On their way to Moonstar's cabin, they had a conversation where Blindfold implied Ink was not a mutant. They were successful in their mission, and just after leaving Moonstar unconscious, Ink knocked out his partner, warning her that she should have seen that coming.
Ink was paid to deliver both Blindfold and Moonstar to Cyclops, which he did, though he refused to kill them for him. Later, when "Cyclops" was revealed to be Donald Pierce with an image inducer, Ink had a change of heart and fought alongside the former New Mutants and his team of Young X-Men.
Book Of Revelations
It was decided that the team would continue and that Ink would be allowed to stay even though he worked with Pierce. During the next mission, the team discovered that Ink was not a mutant, causing him to leave the team.
Off on his own and depressed, he got drunk and was attacked by the Hellfire Cult, a group that attacks mutants, the irony was not lost on Ink. Cipher showed up and told Ink that the team needed his help. Resistant at first, he decided to help but went to his tattoo artist, the real mutant, and got two more tattoos, the caduceus symbol that heals and a Phoenix Force tattoo. He arrived on the battle field and healed Moonstar, who had been shot and proceeded to take away the powers of all the Y-Men. Using all that power had put the tattoo artist into a coma. It was decided that, even though he is not a mutant, he will stay on the team, because Scott fears him running around unchecked with Phoenix-like powers.
Ink befriended Graymalkin, both of whom are new to the X-Men family. Ink asked about Cipher, but Cipher, who was eaves-dropping, bursts in and stops the conversation. Shortly after this, when Danielle Moonstar found Dust dead, Ink attempted to use his untested Phoenix Force tattoo to revive her. Dust was revived, though the strain left Ink catatonic.
As of recently, Ink has been seen at the Jean Grey School 
Ink has no powers of his own. Instead, he had access to a mutant tattoo artist, Leon Nunez, with the power of granting superpowers to other beings by tattooing iconic power symbols on them, evocative of the power he wants to bestow. The downside to this is that it takes away a little bit of his will every time he does it. Nunez made Ink believe that his powers were his own, purposely misleading him into believing he was a mutant. Since granting Ink his last tattoo--the Phoenix Force symbol around his eye--Leon Nunez has been in a catatonic state.
Ink has been shown with the following tattoos and powers:
The tattoo on his right palm in the shape of a biohazard symbol which causes his victims to become extremely ill.
The tattoo on his left hand gives him super strength. The lines look similar to the banding on Colossus' flesh when he transforms, indicating a toughening of Ink's flesh also.
The two lightning bolt tattoos on his head give him telepathy, but this can be blocked by psi-shields. The design was taken from a comic book depiction of psychic abilities (actually an early Marvel Comics publication image of Professor Xavier).
The tattoos of wings on his back grant him flight.
The "explosive" symbol tattooed on his right bicep allows him to blow up objects and punch through walls.
The Caduceus symbol on his left hand grants him the power of healing others.
The Phoenix symbol over his eye allows him to produce energies similar to the Phoenix Force, but not actually tap into Phoenix energies.
The power conveyed by Ink's tattoo was intended to approximate the Phoenix Force, accounting for the visual similarities. But it's illogical to posit that those kinds of energies can be created or transferred through something as prosaic as tattooing. No, I'm afraid that we're dealing with something entirely new here.
According to writer Marc Guggenheim, "When Ink gets a new tattoo, he gets a new power. What's cool about him, from a visual standpoint, is he's constantly evolving as we give him more and more tattoos. But as a result, his powers are also constantly evolving."
On the cover of Young X-Men #1, Ink was shown as being bald, even though he has hair inside the book.