Billy Bat.

ビリーバット

Billy Bat (stylized in all caps) is a Japanese manga series written by Naoki Urasawa and Takashi Nagasaki and illustrated by Urasawa. It was serialized in Kodansha's weekly seinen manga magazine Morning from October 2008 to August 2016, with its chapters collected into 20 tankōbon volumes. The story follows the comic book artist Kevin Yamagata as he draws the popular detective series "Billy Bat".