The Diamondback M.C. is a spin-off from the Golden Skulls M.C.
First introduced in Dylan's Book (#8 of the Golden Skulls), the Diamondback M.C. has suffered a torrid, heartbreaking past. Left behind to grieve, the remaining brothers of the club try to find their way out of the darkness.
This is a standalone series.
There might be small moments of a continuing story line, but each book can be read on its own.