A person with a hobby gone serious.
Kalle is a young(ish) game enthusiastic and game designer. Since he was a kiddo, he has been designing and crafting his own games for fun. Noticing that boring and unpractical hand-crafted games are not bestsellers amongst the broke preteen kids, he started to design more enjoyable and approachable games for people who understand. He also became (more) adult.
Some people have described him "the most prominent game designer in the world", but most people haven't. So probably it is for you and your friends, who have to make the call.
His first published game will be a block war game of 1918 Finnish civil war.