Dr. John is a character that appears in the John Smith 10 franchise and in Omnimania. He is an alternate version of John, and the first one introduced to be a villain besides Eon.
Dr. John is from Dimension 22, which is based off the manga One Piece. This Dr. John works for the Navy, being tasked with creating the Pacifista and Shiro Kuma robots. He is highly hateful towards pirates, and claims that he is a hero in fighting them. He has eaten the Alien Alien Fruit, which transforms into an alien. The body resembles a Grey Alien, wielding several tentacles. He can uses telekinesis and break into golden dust when attacked. He is eventually defeated by Omni, frozen.
Dr. John is one of the primary villains in Omnimania, being in direct opposition of the Omni Crew. He is the creators of both Metal John and GIR, and is in direct allegiance with Eon.
Dr. John, in Dimension 22, is an apprentice of Dr. Vegapunk.
Dr. John's alien form's appearance is based off the Yu-Gi-Oh! monster Alien Mars.
Dr. John's Alien Alien Fruit is a Mythical Zoan Fruit, with properties of all the different types of Devil Fruit.
Since Dr. John is in the Navy fighting pirates, it could be argued that he is a hero in his home dimension. However, since the series depicts the Pirates as the good guys, he is on the side of evil.
Dr. John was brought back to be a major villain in Omnimania.
Dr. John is one of the few characters in Omnimania to not have any powers or transformation capabilities.