Bastard!! is a manga by Kazushi Hagiwara. It first appeared in Weekly Shonen Jump in 1988 and continues to be published irregularly in Ultra Jump. It's currently ongoing with 26 complete volumes. Volume 27 is currently in the process of being published.
The story focuses on the adventures of Dark Schneider, the most powerful wizard in the world. He takes on fellow magician warlords that used to be his top generals, the "god" of destruction Anthrax, and eventually the highest angels and demons.
The series was inspired by Hagiwara's love of Heavy Metal music and fantasy. Many characters and spells are named after mangaka's favourite bands.
Additionaly, a 6 - part OVA was released in 1992.
It's worth mentioning that the manga has badass main character, epic battles, amazing artwork and interesting plot.
Standing in the Arena:
Bastard!! is a very powerful verse. There are casual galaxy busters, characters have feats of shattering dimensions and blackholes. They also have broken techniques, defense, regeneration and massively FTL speeds.
The series is still ongoing so it would likely gain an increase in power in the future.
Badass Main Character:
Riders of Havoc:
- Kal Su