Hal-G (Earth-101001)

Hal-G was a major antagonist in the first installment of the anime series Kingdom Hearts. He was transformed from Michael Verdant, Bridget Verdant's grandfather, when one of his experiments went wrong and Red Core Energy possessed him.

Story
While working on a dimensional transporter, he accidentally crossed to Vestroia, where he encountered Naga and inadvertently caused the beginning of Vestroia's collapse. His Guardian Vessel is Naga. Upon his return from Vestroia, he found that the creatures called Bakugan had come to Earth and that the children of the world gave their powers that although a Conduit can unlock his/her ability this way, the power will not appear until an event occurs that causes pressure on the Conduit.

He was first seen during a video log of Michael where he suddenly transformed into Hal-G, which was caused by a massive outbreak of negative energy. He later appears after Masquerade/Bridget and Osmosis's battle, explaining that while the massive outbreak of negative energy transformed him into Hal-G, it transformed her into Masquerade.

After that, he uses his transporter to send Naga and his minions to Earth to take the Blue Core from Wavern, since all of the Battle Brawlers were stuck in Vestroia.

After Bridget, Klaus Von Hertzon and Christopher defeated Rabeeder, he tricked Bridget into thinking that he was her grandfather trying to fight off Hal-G's control. Bridget then took him to Stark Tower to see Wavern, thinking she could help him. However, once he got close enough, he sent out Naga to destroy Wavern. After Chan Lee Ace and Kai showed up, he battled them and won with no trouble. After Wavern sacrificed herself and the Blue Core was in Drago, he battled Osmosis for it. After seeing both of their Bakugan evenly matched, he brought out the Fifth Paladin and backed Drago in a corner. However, the rest of the Fusion Tenders defeated the 5th Paladin, while Ace, Osmosis, Drago and the rest of their friends defeated Naga, Kurata, and Hal-G.

After Naga's defeat, Hal-G was expelled from Michael's body.

Trivia
Hal-G shares similarities with Mal

Both of them are the clones of the hero

Both of them take over the protagonists' minds