Real-life superheroes with names like Vortex, Midnight Highwayman and Fallen Boy patrol San Diego's streets at night armed with radios, first aid kits and self-defence weapons.

Xtreme Justice League San Diego
Members of the Xtreme Justice League stand watch on a street corner during a patrol in downtown San Diego, California. (L to R) Fallen Boy, Freedom Fighter, Mr. Xtreme and Vortex (Mike Blake/Reuters)

The Xtreme Justice League have a serious task at hand: they walk through dark, empty streets, check in on the homeless and even break up fights in their effort to stop violent crime in the city.

The league was started by Mr Xtreme in 2006. "I do this to make a difference. We have about 20 members that are committed to stopping crime and violence, making a difference, raising awareness and spreading good will in the community", he said.

Xtreme Justice League San Diego Mr Extreme
Mr Xtreme goes over his notes before he and the Xtreme Justice League speak to a local children's karate class about bullying (Mike Blake/Reuters)

"I've actually saved a life volunteering, so I know from true experience that what we do is very valuable and meaningful. If I was not there, this person might not have lived. So even if some people might think it's ridiculous, I know it's not."

Vortex says: "If there's a situation and the cops are not present we could always do a citizens' arrest or defuse the situation. We are the eyes and ears of the streets."

Reuters photographer Mike Blake spent time patrolling the streets of San Diego with the Xtreme Justice League.