Neptune King

Neptune King, also known as Big The Budo, is one major antagonist of the manga and anime series Kinnikuman.

He was the leader of the Perfect Chojin faction and tag team partner of Neptuneman.

Story
Neptune King was originally a student under the one of the original Perfect Chojin, Psychoman, who taught him how to use the Magnet Power. Becoming a member of the Perfect Large Numbers, he eventually grew arrogant and was stripped of his rank by Psychoman. After this, Neptune King left with his group of subordinates, which he labelled as the main Perfect Chojin.

Having left the Perfect Large Numbers, Neptune King entered Chojin Tournaments within the mortal realm. However, he became disgusted as the competition shifted from strong vs. weak death matches into a commercialized sport. He then went into hibernation under in the River Thames. He remained there for thousands of years until he was discovered by a Chōjin named Kenkaman (Quarrelman). Quarrelman was trying to commit suicide by jumping into the river because he couldn't find any opponents strong enough to defeat him (even the british champion Robin Mask was too easy for him). Together, the two of them plotted to bring the Chōjin competitions back to its bloody roots and make the Perfect Chojin the rulers of planet Earth. Then Neptune King gave Quarrelman his Neptune Mask, making him Neptuneman, and created a new masked identity for himself- Big the Budō.

Dream Chojin Tag Tournament saga
He and Neptuneman entered the Universal Tag Team Tournament as the Hell Missionaries with the intention of stealing the masks of the Chojin champions and give them to their henchmen, so that 'Kinnikuman' and 'Robin Mask' would be their henchmen, if only in name. They appeared disguised at the beginning, revealing themselves to punish Screw Kid and Kendaman for their loss against the 20 Million Powers, Buffaloman and Mongolman. They faced the Chojin Master-Student team of Robin Mask and Warsman, who they beat and stole their masks. In the next round they fought the 20 Million Powers, ultimately defeating them and unmasking Mongolman to reveal Ramenman. In the final round, they fought the Muscle Brothers, Kinnikuman and Kinnikuman Great(Terryman in disguise), in a three round match. In the first round, He and Neptuneman won by Cross Bomber, revealing Kinnikuman Great to be Terryman, who had taken the role after the real Great, Prince Kamehame, died. however, they lost to Kin and Terry in the next rounds, when Big began using the swords in the 'Sword Floor Death Match' he designed. This caused Neptuneman to turn on him, as using weapons was against the rules of Perfect Chojin. Eventually Neptune King and Neptuneman were defeated with the tag finisher Muscle Docking.

Scramble For The Throne saga
When the Five Evil Gods discussed Kinnikuman's growth in power, the evil god of intelligence revealed the beaten up body of Neptune King as testament to it, with several of the Gods remarking how unbelievable it was for the 50,000,000 power Perfect Chojin to be defeated by Kinnikuman.