Some TMNT stuff was always meant for grownups.
Arnold Casey Jones (retconned from earlier Casey Bernard Jones) is a character from Teenage Mutant Ninja Turtles. Like the Turtles, Casey Jones is a vigilante, and was created as a parody of vigilante characters that were in comics. Casey wears an ice hockey goaltender mask and cut-off biking gloves and carries his weapons in a golf bag over his shoulder. His weapons include baseball bats, golf clubs, cricket bats, and hockey sticks. In most installments, he appears as a love interest for April O'Neil.
Casey Jones grew up in Brooklyn, a neighborhood in New York City, which is not exactly known for its safe environment. When Jones was young, his father, Herb, owned an auto shop. A group of Purple Dragons members (lead by a young Hun) burned the shop down, killed him and took his wife and daughter hostage. The badly beaten Casey refuses to lie down and takes Hun’s blows. He attacks Hun with a knife, stabbing him in the neck. Enraged, Hun beats him to within an inch of his life. It seems that the beating he took from Hun as a teenager resulted in several mental and emotional disorders, explaining his often violent and erratic behavior. He had no friends and spent his spare time watching the programs on his three televisions, which he ran at the same time and eroded his rational thinking skills over time. Enticed by role models from diverse action television series', Casey decided to do away with the "scum and dirtballs" of the streets. After he had equipped himself with a hockey mask and various sports clubs, he began his vigilante campaign.
Casey Jones first appeared in the Raphael solo issue "Me, Myself and I". Raphael runs into Casey beating some muggers and proceeds to stop him before the crooks are murdered. Jones and Raphael fight several times before making peace with each other and helped each other to take down a group of muggers. Later, he comes to the aid of the Turtles, Splinter and April O'Neil when they are attacked by the resurrected Shredder at April's home. The seven escape, and retreat to a farmhouse in Northampton, Massachusetts that once belonged to Casey's grandmother. Casey "officially" becomes a part of the Turtles' family around this point, and the farmhouse acts as a second home to them all for some time. At first he and April are not really close, but over time they became closer.
In the Mirage series, Casey is extremely violent, even more so than Raphael, but mellows throughout the course of the series. In "Shades of Gray," he accidentally kills a teenager who tried to mug him. The incident sent him into a drunken spiral, damaging his relationship with April O'Neil, and he began to rethink his role as a vigilante. His initial homicidal tendencies are especially present in his first appearance, although he never actually murders anyone in that instance. It is later revealed in commentary on this miniseries by one of the initial creators (Kevin Eastman) that they had intended for Casey to have become a vigilante because he watched too many bad cop shows (like Peter Laird used to), as opposed to the more popular storyline of the hero doing the same thing after seeing their family killed in front of them. However, this is semi-retconned when writer Tristan Huw Jones imported his 2003 TV series backstory, in Tales issue #56.
During "City at War", Casey leaves the farmhouse and begins to drive to Los Angeles, planning to find April, but instead meets a pregnant woman named Gabrielle, a waitress in a small diner in Colorado, with whom he falls in love and marries. Gabrielle dies during childbirth and Casey is left to take care of her daughter, whom he names Shadow. After spreading Gabrielle's ashes, Casey returns to New York City with Shadow to stay with his mother. In a chance encounter, Casey is reunited with April when she comes to buy the apartment building owned by Casey's mom. During this meeting it's revealed that Casey's real name is Arnold. Casey repairs his relationship with April and they begin dating.
By volume four, he and April are married. They raise Shadow as their daughter and try to have a child of their own. April eventually leaves Casey and Shadow when she learns that she is not human and is a product of the Kirby warp pen. As April comes to terms within herself in Alaska, Casey takes to the nightclubs to drown his sorrows. He meets up with The Foot Clan leader Karai at one of these clubs and, after a few drinks, awakens at Karai's retreat with no memory of the night before, although Karai knows something of what had happened. This plotline was left unresolved as the fourth volume came to an abrupt end. Often Casey has been known to shout the term, "Goongala," as a sort of battle cry.
Casey is often wearing his mask when he goes to fight crime and his constant weapons are an ice hockey stick, baseball bats, and golf club.
- Kevin Eastman said his personality was based off Kurt Russell's character Jack Burton from Big Trouble in Little China. However, Casey Jones' first appearance actually predated Jack Burton's first appearance by a year.