Orphan X

Evan Smoak was taken from a group home as a boy and raised inside the Orphan program, a secret government operation that trained children to become deniable assassins. He was Orphan X. After breaking with the program he disappeared, and he now lives quietly in a Los Angeles apartment building where his neighbors believe he imports cleaning supplies.

In secret he is the Nowhere Man, a figure whispered about among the desperate, who helps people with nowhere else to turn. Each person he helps repays him by passing his number to someone else in need.

When a woman calling herself Katrin White asks for his help, the job quickly turns dangerous. Someone with training much like his own is on his trail, and willing to use his secret identity against him. Orphan X, published in 2016, is the first book in Gregg Hurwitz's Orphan X series, a fast-moving thriller about a lethal man trying to do some good.