Harold Lilja (Batman/TMNT)

Harold Lilja is a close friend and colleague of. When the Turtles and were sent to a different Earth, Harold worked alongside  to pinpoint their dimensional location. He gave a technological "slingshot" that would allow the Turtles to return, and used an experimental dimensional teleporter to send the young man to Prime Earth.

When Casey returned without Splinter and the Turtles, Harold used his teleporter to send April and Casey back, though there was considerable risk in doing so.

He kept the interdimensional teleporter after this incident, but was not present when Donatello used it to attempt to contact Batman.