Tatsuki Fujimoto Before Chainsaw Man: 17-21

Killer mermaids, gender swapping, and a devilish little sister with the power to end the world—four more unforgettable short stories that reveal the starting point of Tatsuki Fujimoto, the twisted mastermind behind *Chainsaw Man*.

(Source: VIZ Media) 

1. Ningyo Rhapsody (2014)
2. Me wo Sametara Onnanoko ni Natteita Yamai (2017)
3. Yogen no Nayuta (2015)
4. Imouto no Ane (2018)

A strange world where aliens have taken over the human world, and only two humans are left which are apparently disguising themselves as mere chickens.

Fujimoto Tatsuki's first one-shot when he was only 17, and it also contains a special interview section!

To Sasaki, his teacher Kawaguchi is God. She taught him not to be ashamed of his own dreams and made him feel fully capable to forge forward and make them come true, no matter how low the odds. Yet one day, trouble from Kawaguchi's past follows her into the classroom. With his god in danger of total humiliation, Sasaki sets out to protect his teacher using her very own teachings: to strive for the impossible. 

(Source: MAL Rewrite)

A one-shot story about a boy that is blind to everything but love.

A notorious hit-man bites off more than they can chew when their newest target turns out to be holding a supernatural secret. Bullets fly and love is in the air.