Rebirth in One Piece as Deputy Captain - Chapter 411

Silas Blackwood wakes up with a machine in his chest – his missing mother's parting gift to help him survive the war with the Fae. This “system” grants him bizarre abilities: neuromancy (magic of the mind), biomancy (magic of the body), and essomancy (magic of souls and essences). Oh, and it fused a leviathan's mana core into his body. Because why not become part sea monster?At Arcanium University, a military boot camp churning out mage knights, Silas finds himself targeted by rich brats who think being born with a silver wand up their ass makes them special. When they leave him for dead, Silas decides it's time to show these spoiled kids what real power looks like.As Silas grows stronger, he discovers he can upgrade himself by absorbing essences from magical beasts and demons. Just when he thinks he's got a handle on things, Silas learns his mother's alive, and now he's got a new mission: a rescue that'll take him and his friends straight into the depths of Hell.

My Beautiful Teacher tells the story of a university graduate Qin Chao who can’t seem to find a job and is in a downward spiral in his life. Then one night as he walks home from another failed job interview, a vase hits his head, making him get possessed by an old and powerful evil spirit sealed in that vase and following another incidents, inadvertently saved a mysterious university teacher Su Ji, thereby opening his path to cultivation, he also manages to get a job as a security guard at Guangyuan School. A series of adventures then took place as he deals with all kinds of supernatural beings.

- Description from Novelupdates

Dying at a young age after a disappointing life. Mat thought he hit the jackpot when he got reincarnated on a tropical island as a baby. Here, exploring mysterious lands and learning magic are a reality. The world of Elydes is beautiful and magical, wild and savage. While the Guide is impartial to all, people are not. Mat has the lowest starting point possible, and those like him rarely go far. To not let his humble birth define his life, he'll need to find the determination to grow stronger and delve into the mysteries of Elydes.

Just something I made to keep track of some of my favourite essences & powers from fics. {with personal twists}