Crocodile

Crocodile was a criminal who once thought it would be a good idea to fight Ynot. Unsurprisingly, he lost, and was imprisoned in Impel Down as punishment.

When Blackout attacked Impel Down, Crocodile was one of the prisoners who was freed by his forces in order to cause chaos. However, Crocodile avoided Blackout's Rahkshi and chose not to be teleported away; instead, he headed back into the prison to salvage whatever he could. He would later likely end up regretting this decision, because once Blackout's forces left, he found that he had no way of getting off the planet.

In fact, Crocodile was still on Impel Down just before the Battle at the Omega Point. During the battle, User MY remembered Crocodile's skirmish with Ynot, and decided that Crocodile would be a good character to use against Blackout. MY used his author powers to teleport Crocodile from the ruins of Impel Down to Blackout's location, but... this apparently failed. Instead, Crocodile failed to materialize, and has not been seen since.

Trivia

 * Crocodile failed to materialize in the Battle at the Omega Point because User:Zev was not around to consent to his usage. Who knows where Crocodile ended up instead, if anywhere...