Legend of the Dragon Kings (1991)

Blurb:
There’s something strange about the four Ryudo brotheres. Each seems to be endowed with almost superhuman abilities. But someone out there is envious.

Kamukura no Gozen, the 'old man of Kamukura' is the richest and most powerful man in Japan. He also seems to know more about the brothers than they know about themselves. He’s spent his entire life trying to unravel a secret so important, so powerful, that it’s worth any price. And somehow, the brothers hold the key to that secret.

Until now, the brothers have led a pleasant, peaceful life.. But all that is about to change. They weren’t bothered when the assault and kidnapping attempts were directed at them... But when their friends become victims, it’s time to get tough. Unfortunately, no one knows how powerful the brothers really are - but they’re about to find out!

Source: www.anisearch.com/anime/880