The mixed martial arts community is mourning the loss of UFC title challenger Anthony "Rumble" Johnson.

His death was announced Sunday, months after revealing he was battling an undisclosed illness.

After years in the UFC, Johnson signed with its competitor, Bellator, and was poised for a title shot before becoming ill.

"The BELLATOR family is devastated by his untimely passing and we send our condolences to his family and friends during this difficult time," the promotion said in a statement.

Johnson's former competitors paid tribute to the fighter on social media.

Former UFC champion Daniel Cormier said Johnson was a caring person who will be missed.

"Sometimes life doesn’t seem fair," Cormier said. "Horrible news."

Glover Teixeira, a former UFC champion who lost to Johnson, recalled their time in the cage.

"One of the most scary & tough opponents that I had ever faced and one of the nicest and most humble humans I have ever met," he said.

Johnson began his professional mixed martial arts career in 2006. He last fought in 2021, beating José Augusto Azevedo. His professional record will stand at 23 wins and six losses.

Johnson was 38 years old.