Can a fictional character be a Kami?

I have followed Shintō traditions for many years but I’ve never actually asked many questions, this last week a friend from Europe brought up a very interesting question. Can a fictional character be a Kami? And can you make up your own Kami?

I don’t know the answers to either of these personally and I don’t want to act like I’m a professional, does anyone have a good answer for these questions?

Like, within the context of a fictional work? Sure - when you're writing fiction, you can do whatever you want. No different than writing a story where a fictional character is an angel or you make up a new god to be part of the ancient Greek pantheon.

But do you mean "Can a fictional character become recognize by real-life Japanese Shinto worshipers as a kami?" or "Do real-life Shinto worshipers in Japan make up their own kami?" then the answer is no.

That's the same thing as asking, "Can Thor be a god? And can you make up your own god?"

Can one assign a specific thing to a deity? I am sure there was no kami for "road safety" but there is now. So can things be assigned to kami that weren't their domain?

「Can one assign a specific thing to a deity? I am sure there was no kami for "road safety" but there is now. So can things be assigned to kami that weren't their domain?」

You might be misunderstanding how the Shinto religion works. There is no official "kami for road safety." What there are are kami who traditionally are believed to watch over travelers, and by association in modern times may be thought to watch over drivers.

A similar example: Inari Okami is often thought of as the kami of businesspeople, but that's not an official part of Shinto doctrine. Inari Okami is the kami of rice. Back in the old days of Japan, you were generally a farmer, a warrior, or a priest. Some of the first people to conduct "business," though, were rice merchants, and so through the connection to rice, many people began to think "Hey, I bet Inari Okami probably watches out for rice merchants too," and when people started selling things other than rice, the mental association continued.

You ask "can one assign" and "can things be assigned to kami," but unlike many other religions, Shinto doesn't have a governing body or singular authority. There's no equivalent to the pope or dalai lama who makes decisions and edicts about what is and isn't canon, and a lot of beliefs and traditions develop organically and separately at different shrines/in different regions.

There's no head honcho or council of elders that gets together and decides, "Oh, video conferences are now a thing? OK, then let's debate and vote on who should be the kami of video conferences, and then we'll make an official announcement so that people know which kami to pray to before they log in for their Zoom meeting."