Disclaimer: I do not own Harry Potter nor Fate/Grand Order, this story is my first and a way to handle stress from my schoolwork so they will have grammatical errors in it, please be kind with the criticisms. This story is inspired by Lothlorien-23's My Strange Family. The story will have bashing Dumbledore, Order of the Phoenix, Potters, Weasleys (except for Ginny, Fred, George Neville, and Hermione)

Ch 1 Prelude

Harry Potter or should I say Ritsuka Fujimaru had a difficult childhood. His parents neglected him and paid more attention to his twin brother Charles after Voldemort attacked and the defeated at Godric's Hallow believing to be The Boy Who Lived receiving a scar on his left side of his forehead while Harry to have on his right side on his.

By the age of 8 his parents sent him to his aunt Petunia where he abused and neglected even more. Both his aunt and uncle encourage his cousin to beat him along with his friends. When his aunt Marge came to visit his magic core overloaded causing a magical mishap that causes her to blow up like a balloon, doing that cause his magic core to be destroyed beyond repair. After that he left the Dursleys and decides to live alone away from this country.

He went to Gringotts to withdraw from his vault in the Potter vault knowing that his money can be tracked. Thanks to his account manager and the goblin king Gringotts they provided him to transfer his savings to a private vault with the bank so that no one can track him. He also requested to see his inheritance and was shocked to see that he has dormant magic circuits and the Potters were once a mage family dated back to his great grandfather.

Harry decides to pursue his family's work of gem magecraft where his great grandfather has left off and claimed the Potter family's crest for his own. Once he was set, he asks Gringotts were would a could practice magecraft and he recommended Fuyuki Japan. Once Gringotts cast a translated spell on him he then got settled in his apartment in Japan, he meets someone that help him in getting him a job.

Flashback

Ritsuka finished with his work at his part-time job as a convenience store clerk to gain some more extra cash. He opens the door of his apartment and flops down on the floor after a stressful day of work. He turns on the TV and checks his mail in his hand

"Junk, junk, junk, and more junk." He threw each junk mail in the trash bin as he got up to make dinner for himself, he sat down with a plate of curry as he looks at his arm mentally activates his magic circuits. He sighs "I should really look for a book or something about magecraft." He said to himself, he looks away from his arm when he heard a knock on his door. He got up walking to the door and open it to an old man standing there with a grandfatherly smile.

"Excuse me young man, but I saw you exiting the convenient store earlier and wonder if you were looking for a well-paying job?" he asked the young magus.

"What kind of job?" Ritsuka can't help but ask, in his mind he thought it was strange that this man knows that he was looking for a job and on the other hand the salary he was on isn't paying enough for his bills. The old man handed him a flyer and he read it

Chaldea Security Organization

Apply for a slot for a master candidate

Salary of 1,500 per month

Location XXXXXXX

Contact XXX-XXX

"(This flyer seems suspicious; but the pay is good, and it doesn't require to be a high school or college degrees. Maybe I should accept it.) Ristuka thought as he made his final decision. "I accept the job, uh…what's your name sir?" he asks the old man. He smiles at him "Zelretch, my name is Kischur Zelretch Schweinorg, and here." He handed him the Chaldean uniform placing it in his arms.

"Wait- "he tries to say something to him, but he disappears and can't find him anywhere. He went back inside and call the number listed on the flyer.

End of Flashback

Before he knows it, he met a lavender hair girl named Mashu and travels back in time to correct human history to various places from being incinerated and different worlds in the Lostbelts. He had made friends with heroic spirits and the people who live within them. All the servants that made contracts with and the ones who were enemies have decided to stay with him in Chaldea to help to protect his goal to protect humanity.

Even the Beast class decide to be with him making him Humanity's last Master. After the battle against Goetia in the temple of time, Romani's fate, and Lostbelts he was given the position of director at a young age by the UN and the Mage's Association. He also dealt with a lot of hardships and losses in the Singularities, Remnants, and the Lostbelts even Pseudo-Singularities and somehow manage to push through them.

Mashu was a big help during his time in Chaldea, even dealing with the constant arguing between Kiyohime and Tamano about which is the more faithful bride is for him. He cherishes the moments with his servants and staff at Chaldea hoping nothing will ruin it.

Back at Hogwarts

Dumbledore didn't notice that the instruments that were supposed to check on Harry had stopped working since last year. He has preoccupied with Beauxbaton Academy and Durmstrang Institute's arrival for the Tri-Wizards Tournament to think to check on him with the dementors on the school grounds and the traitor Peter Pettigrew to be the real traitor to the Potters last year his mind was on Charles Potter.

Chaldea

Ritsuka was in his office writing reports to the Association when Merlin barged in unexpectedly. Agravain, Nobukatsu and Mashu look at the Magus of Flower. "Merlin, what brings you here?" Ritsuka asks as he places his pen down to face him. Merlin was nervous to say what he wants to. "Ah, yes um…Master there's seems to be a situation in the near future that Chaldeas has detected."

"Are you saying that a grail has emerged, Merlin-san?" Mashu asked. " Impossible! Goetia said that all of the holy grails have been collected and currently stored in the vault!" Agravain exclaims. "I have consulted with Goetia and he remembers that there was an unstable grail that he did not use and threw it away in a timestream and somehow falls into the wrong hands. Merlin explains to them. "Regardless, if its unstable we must destroy it before it causes some damage, Merlin, where did exactly, said it was?" Nobunkatsu asked. Merlin's was silent making everyone to worry, he turns to his master "You may not like it, Master,"

Ritsuka gave a cold look making him more nervous. "Its…its in the hands of the people who have abandoned you at a young age." Every servant knows the story of his past and how they treated him. They turn their heads to their master who hides his face, "And it's being used as a trophy and a selection tool for the Tri-Wizards Tournament, and your old name was called." A loud thug spooked them and know who did it "Senpai?"

"Tell everyone to get back to work and prepare for the worst scenarios that might happen." He said darkly then chuckles making everyone worried for him especially Mashu. "What has that old fool done?"

AN; For future reference after the Lostbelts Gordolf Musik steps down from the position of director of Chaldea and gives it to Rituska seeing how capable he was during his missions. The Mage's Association and the UN fund Chaldea and given the task of protecting the world from threats. Please leave a comment on whether you like or not.