An assassin who cannot kill x A young man who cannot see
 
"If you discover my true form... I am sure I will leave you disappointed."
 
Chinatsu, a young man born into a family of assassins and living his life in the underworld, could not kill anyone because of a trauma from the past. When his brother died in front of him, a child extended his hand to him, and the image of that child was burned into his memory. After reliving that nightmare, Chinatsu was reunited with the boy, Kasumi, from that day. Knowing that Kasumi could not see, Chinatsu agreed to be his friend, but...
 
A young Chinatsu tormented by his family's past, and Kasumi, the blind but innocent soul. A story of salvation for two people who live in darkness.
 
(Source: Renta, translated)
 
Note: Chapter count includes one extra.