There are multiple artists called Roi so their stuff are getting mixed up on Spotify and last.fm, but you can find him on YouTube @Roiwoof, I also have a playlist on Spotify so I don't mix up his songs with the other Roi: https://open.spotify.com/playlist/3HqmGEzixk7fJxN77LG9G6?si=9fcb70c1b9104d71
He's a Japanese artist with two original songs at the moment (Three if you include Nikukyu, the two are called Gemini ((Also known as Gemini Man)) and Boku wa Jinro), I don't know enough about music and stuff to be able to sort them into genres so I can't give you information like that, but I think his songs have a more upbeat tone (Other than Nikukyu, which is calmer) and generally have some focus on the guitar
Other than his music I like the mvs as well, it's said that Boku wa Jinro and Gemini are probably set in the same universe. Both mvs were animated by Studio Lico (Most known for Alien Stage), Boku wa Jinro was directed by Vivinos and QMeng (Creators of Alien Stage), and Gemini was directed by and Dust Girl Yoruke
My personal favourite song of his is Gemini, as is probably obvious by my previous statement of me failing to make it my top song, maybe next year
I think that's enough ramble sorry if this isn't quite what you're looking for I'm just saying whatever I think is necessary information for someone who doesn't know Roi to know haha