Q to T (Older Teen) 

Seraph of the End: Guren Ichinose : Catastrophe at Sixteen

by Takaya Kagami

A prequel to Seraph of the End, this is the story of Guren Ichinose who ends up the leader of the moon demon company, this is how he got there.

Spy X Family 

by Tatsuya Endo

A spy tasked with 'building a family' to execute a mission he is on adopts a telepath and 'marries' an assassin. Both of which he has no idea about. 

The Promised Neverland 

by Kaiu Shirai

The orphans at Grace House have only ever known peace. Nice home, nice food & a 'Mom' who loves them all very much, everything comes crashing down when the 3 very smart children become aware of what happens on 'adoption' day.

The Strongest Sage with the Weakest Crest

by Shinkoshoto

His strength limited by the magical crest with which he was born, Mathias, the world's most powerful sage, decides reincarnation is necessary to become the strongest of all. Upon his rebirth as a young boy, Mathias is thrilled to discover he's been born with the optimal crest for magical combat on his first try!

Tokyo Ghoul 

by Shu Ishida

A world where humans fear ghouls as they are the same as them except the need to get human flesh in order to survive. Shy, college student Kaneki Ken is nearly killed after a date but as he wakes up something is very, very wrong.

Tokyo Revengers

by Ken Wakui

Hanagaki Takemichi lives an unsatisfying life right up until his death. Waking up 12 years in the past, he reckons with the eventual fate of his friends and tries to prevent an unfortunate future. Takemichi Hanagaki is a freelancer that's reached the absolute pits of despair in his life.