Maybe you had to follow the Japanese MMA scene to appreciate him, but Norifumi “Kid” Yamamoto was one of the greats. And yesterday, the Shooto, DREAM and UFC vet announced that he’s now battling cancer.

His Instagram post is in Japanese, so here’s MMAFighting with the news:

One of the top MMA fighters ever from Japan and a pioneer of the lighter weight classes shared bad news on social media Sunday.

Kid Yamamoto wrote on Instagram that he has been diagnosed with cancer and is currently battling the disease. Yamamoto wrote the post on Instagram in his native Japanese, but it has been translated by multiple outlets.

Few details are known outside of his diagnosis and an apparent promise to return to fighting.

Yamamoto, 41, was one of the top smaller fighters in the world in the mid-to-late aughts. “Kid” won 14 in a row between 2002 and 2007. He owns victories over the likes of Bibiano Fernandes, Roller Gracie, Genki Sudo, Caol Uno and Jeff Curran. Yamamoto (18-6, 2 NC), whose real first name is Norifumi, has 13 knockouts in 18 career wins.

By the time he finally got to the UFC, Kid Yamamoto was a shadow of his former self. But take my word for it, he was a badass in his day. Here’s hoping he makes a full recovery.