This Leatherhead is somewhat more enigmatic than the other versions. He is a true friend to the turtles, but is still rather untrusting of most people.

Of course, being the Mirage version, he is also the original,
thus a more involved and complex character.

(I wonder who that could be on the calendar?)

Leatherhead was once a normal pet alligator, that was flushed into the sewers.
He inadvertantly came in contact with the Utroms (the creators of the ooze -- think Krang), who experimented their mutation causing agents on him. Of course, he grew in intellect and learned all about the Utroms knowledge of space travel.

Knowing that he could never be part of the human's world, he decided that he wanted to join the Utroms and live on another planet that would accept him.

For some reason he was left behind, and has been trying to get his space travel transmat in working order.

He is a much more sad character -- with good reason. For instance, in this issue, he has enlisted the help of the TMNT and a few stray Footsmen to build his transmat.

The machine will help him find the Utroms and ultimately take home. But, the Foot Soldier (from whose point of view we are reading the story) removes an integral piece of hardware that causes the transmat to explode.

Thinking the Turtles were the ones behind the malfunction,
the heart broken Leatherhead vowed revenge on them.

Too dismayed to fight, he leaves to be "... alone ... forever ..."
Read my first Leatherhead fan-fic, "Croaker," to find out what happens next!