Henry Orville Leopold
Henry Orville Leopold is a holographic character in a steampunk-themed holoprogram on the USS Discovery-C. The character befriended Raj Blueheart during the time Blueheart was trapped in a never-ending loop in the holodeck. Since then, Mr Leopold has made at least one attempt to materialize outside the holodeck to meet up with Blueheart. He has provided Blueheart with a communicating device called the Farnsworth, if Blueheart ever wishes to communicate with Mr Leopold outside the holodeck.
Unbeknownst to Blueheart, when he inserted his personal data cube into the USS Atlantis's Holodeck 2 to run a 15th-century French cavalier holoprogram on stardate 239102.10, Mr Leopold was happily transferred into the ship's holodeck subroutines and pattern buffers!