Origins (House Phoenix #0.5)
S.W. Vaughn

"A Dangerous Gift": When three-time tournament champion fighter Marcus Slade decides to bow out of the game and hire his own stable of bloodthirsty brawlers, his employer offers him a parting gift he can't refuse -- one that may prove more harmful than helpful in his new venture.
"Role Reversal": After Sol manages to destroy his football career -- and that of his twin brother, Apollo, in the process -- in a vicious bar fight, he's sentenced to anger management with a very unusual doctor... who, instead of healing him, is unraveling the last of his sanity.
"House Call": Having lost his license to practice medicine, Seth "Doc" Stephens is approached by a now-former patient with a big problem in the form of a nasty criminal boss. But when Doc confronts the man, he realized he might have stepped into something he can never escape.
"Badder Than Hell": Aidan, the new lieutenant of House Prometheus, is out with the gang to break in a new recruit -- preferably with a bruising bar brawl. Unfortunately, their target for the evening has some really big friends waiting in the wings.
Bonus full-length novella!
"The Boy Who Never Was": Young Sunil has never had it easy. His parents despise him, his brother frequently thrashes him, and everyone in his village does their best to pretend he doesn't exist. But Sunil prefers being shunned, and left to his own devices -- until one day, a Japanese hunter arrives in the village and negotiates to purchase him as a servant.
Sunil is brought to Japan and placed in the sole charge of the hunter's son, the cruel and sadistic Tomi Harada. Despite gaining a single friend -- a servant boy who seems happy to ignore Sunil's darker qualities -- he is forced to cope with unending brutality, until he can learn to extract respect from his heartless master. By any means necessary.