Yasuo is a popular League of Legends champion, so 'Yassuo' is a homage to it.
While he was in high school, he would spend all of his free time playing video games. When he felt that he had gained sufficient skills, he decided to start streaming for an hour or two at a time to see what would happen.
He managed to come across pro players while he was recording his ladder climbs and uploaded them onto YouTube. This quickly gained him recognition and followers in the League of Legends community. After high school, he wanted to pursue a streaming career. His parents were not supportive of this originally, as they wanted him to study in university. Fortunately, he started earning enough money to pacify his parents. His little sister often features in his streams. His streams are not kid-friendly.
He lives with his family and often hangs out with his younger sister.
Yassuo is estimated to have ~3,400 subscribers. This would minimally net him $8,500 USD per month, excluding income that he would make from sponsorships, shoutcasting, his Counter Logic salary, tips Twitch Cheer Bits, advertising and tournament winnings.
Yassuo has an inconsistent schedule due to his tournament and shoutcasting obligations, but he tends to stream at least a couple of times a week.
Start streaming immediately, and as much as possible. Make sure that you’re consistent and that you are active on all social media sites. You can’t just stream for eight hours a day. You also need to promote yourself on Twitter. Make memes and get yourself known. If people find your clips and memes funny, then they will click through to your Twitch channel. It’s also important to collaborate with YouTubers and to comment on other streamers posts.