Atsushi is an adorable little boy and Chin's 9th adoptive child. 

(Background)

He was abandoned from his mother as a baby and was raised in the Yokohama orphanage, where he suffered from verbal and physical abuse from the headmaster/caretakers. 

Because of this, it has taken a huge toll on his self-worth now that he's older, causing him to constantly question the value and usefulness of everyday life. 

Aside from that, Atsushi also suffered at the hands of the other orphans as well.  

They'd often throw him off of the bus as it drove in the street, he would cry for help for Akiko to get off of the bus to bring him back in it. One of them even cut his hair as a prank and he had to let it grow as the hairstyle that he currently has.

On Atsushi's tenth birthday, the headmaster chained Kenji and him in a very dark cell with a white tiger that attacked him on his legs. 

When he saw Chin in the cell with him, she unlocked the chain, picked him up and became his current guardian with Kenji by his side.

Height: 4'6

Hair color: White

Birthday: May 5, 2010 (Fan-fiction only), May 5, 2007 (Fanime)

Age: 5 months - 4 (Prologue), 10 (First appearance), 11 (Timeskip), 12 (Currently)

Personality: Very sweet, clumsy, cowardly and awkward.

Relatives: Atsui (Biological mother, Deceased, Reincarnated), Unnamed biological grandparents (Deceased), Chin Xi (Adoptive mother), Yukichi (Adoptive father), Mori (Adoptive great-uncle)

Occupation: Orphan (Formerly) Sailor (Currently)

Affiliation: Yokohama orphanage (Formerly, Chosen to be adopted) Sai ijō no kodomo no ie and sailor agency (Currently)

Relationship with Chin: Atsushi and Chin both share the same birthday and segmental heterochromia. He even has the nerves to call her "Mommy or Momma."

Reference for his voice: https://www.youtube.com/watch?v=0TumS8k8DtQ

Profile pic: https://bsdmayoi.fandom.com/wiki/0108_Nakajima_Atsushi 

Wiki references if you've never heard of this character: https://bungostraydogs.fandom.com/wiki/Atsushi_Nakajima