Shokugeki no Soma x HP

Harry Potter is Jōichirō Yukihira (Saiba)

And Teddy Lupin is Sōma Yukihira

Teddy was blood adopted by Harry when he was around 2-3, just a little before Andromeda Black passes away. Andy's death was also a catalyst for a series of events. Which basically were: Harry blood adopts godson, gathers up all possessions (money and objects), buys a house in Japan, and enrolls in a cooking school (Tōtsuki Culinary School), at this point in time he would be 19-20, but he still looks rather young, or perhaps he took a potion to de-age him like 5 years. Or perhaps when he graduated from Hogwarts at 18 (went back for seventh year after war), he took the potion to de-age him to maybe 14/15 (to escape from the public eye), and went and auditioned and was accepted into Tōtsuki (his heritage did help with costs and all, and well Harry picked up on a subconscious level how to add magic to his dishes to give them that added effect). Harry became the 2nd seat of the Elite Ten of the 69th generation of Tōtsuki students and was known as "Asura", though he never graduated (and I have it this way because Andromeda passes away and he has to take care of Teddy), he only got to his third year. So by the time he drops out he is around 17/18 again (and actually is 20-22 by this point, which is just a year short of how old canon Jōichiru is when he has Sōma). For the timeline to match up completely should Teddy also be given a potion when he is blood adopted to de-age him? Or should I just push forward Sōma's generation by 3 years? (I imagine that the age reversal potion wouldn't be a wise idea to use on children/toddlers).

I also imagine to stick to the Food Wars! canon that when Harry/Jōichiru takes the de-aging potion he also takes one to permanently change his hair to his mother's red hair, which is the shade he has in the manga and the one Teddy/Sōma sticks to. (Sōma has golden eyes [which is where this entire idea stemmed from], which could be his default or to honor his birth father Remus).

In the one-shot Sōma had shorter black hair, and gold eyes.

Though Jōichiru's hair is sometimes depicted as brown. And canonically his eyes are gold like his son's. But I kind of want to keep them Harry's vibrant green.

The Shokugeki Wiki says the Jōichiru travelled the world and became famous for his unorthodox and flexible cooking style, and at 23 married and had Sōma. A few years after this he took up the name Yukihira. (He started his restaurant around this time too I suppose). At 33 he worked for the Nakiri family for a period of time before returning to his restaurant. And then when Sōma is to start high school he goes to New York to work (which forces Sōma to go to Tōtsuki). He also tells Sōma that the restaurant will be closed for 3 years.

So by this point Jōichiru would be 46-48 years old. (Harry would actually technically be like 50).

Jōichirō (城一郎), using the kanji for "castle" (城 Jō), "one" (一 Ichi), and "son" (郎 Rō), could mean "son of the first castle". Yukihira (幸平), using the kanji for "blessing" (幸 Yuki) and "common" or "ordinary" (平 Hira), could roughly translate as "blessing of the ordinary", a reference to the location of his restaurant. His original last name, Saiba (才波), uses the kanji for "aptitude" or "talent" (才 Sai) and "wave" (波 Ba, alternatively pronounced Nami).

Sōma (創真), using the kanji for "creation" (創 Sō) and "true" (真 Ma), could mean "true creation", a reflection of his boundless creativity. Yukihira (幸平), using the kanji for "blessing" (幸 Yuki) and "common" or "ordinary" (平 Hira), could roughly translate as "blessing of the ordinary", a reflection of his humble origins compared to his classmates.

[From Reddit]

So look here: Joichiro decided to use his wife's last name instead of his. Why? Because he wanted to move on from his time as a demon in the culinary world.

After watching this week's episode (16: The Chef Who's Crossed a Thousand Leagues), I realized something. During the Training Camp arc, many of Joey's old colleagues were present as judges during the Camp itself.

Dojima was friends and rivals with Joichiro during their days at Tootsuki, even becoming the first and second Elite Ten seats, respectively. Dojima made notice of Soma walking away at the end of the camp (7 minutes into Episode 15, The Man Called the Demon), recognizing its familiarity to his friend, Joichiro Saiba. It's at this moment that he puts two and two together and realizes that Soma is his old friend's son.

Now, why did old Joey decide to use his wife's name, rather than his own? I bring up the beginning of Episode 2, where he says, "The trick to becoming a good chef is to meet a woman to devote all your cooking to."

This leads me to conclude that Joichiro met Soma's (as of now unnamed) mother and chose to spend the rest of his days making food with her in mind.

His past as a demon in the culinary world (with Shokugeki left and right, ruling over Totsuki as the Second Seat) as well as dropping out of Totsuki while still following his dreams of becoming a world class chef made him realize that that flavor wasn't what he wanted her to taste.

When they got married, he took her last name and passed it onto their son, hoping that little Soma would retain his father's passion for cooking, but not follow in his footsteps. He named his diner Yukihira in memory of his late wife, and as a symbol of pride for the new style he'd created during his time with her.

Joey trained Soma from a young age using the techniques he learned as he traveled the world to give his son a head start when he eventually attended Totsuki. He intentionally goes all-out during his cook-offs with his son to give Soma "the feeling of failure." Soma takes this 100% to heart and uses it as the basis for all of his cooking.

Yukihira Soma is the culmination of his father's travels, technique and cooking style and the passion his mother instilled upon his father to better himself through his cooking.

Or I've been awake for too long and I'm talking out my ass. Take your pick.

In the one-shot, Sōma is 16.

In the first chapter of the manga, it says Sōma is a third year middle schooler who is 15. And that his dad Jōichiru is 38. Sōma also states that he will graduate from middle school in a few more months.

Sōma takes the transfer exam, and then one month later in April is when orientation/start of term happens.