Kieron is best known as a comic writer, including co-creating books such as The Wicked + the Divine, DIE, Once & Future, Phonogram, THREE, Uber and the Ludocrats. He's worked on many books for Marvel, such as Star Wars, Thor, Young Avengers, Iron Man, Uncanny X-Men, Darth Vader (where he co-created Doctor Aphra), Eternals and a load more.
When he's not writing all of that he likes to relax by writing some more, relevantly gleefully amateur game designs. He has fun.
If you want to follow his work generally, it's best to subscribe to his newsletter.