Finn Mertins - The Player of Steven Universe in Steven and the Crystal GMs
Finn was 11 at the time when Betty agreed to watch him while his mom was away for a time. During that time he discovered Betty's old campaign notes and eagerly started to use them to make his own character in Steven Universe, the son of Greg Universe and Rose Quartz, Betty and Simon's characters.
Finn is an excitable and friendly boy. Very eager and believes wholeheartedly in the 'rule of fun'.
He is named for the Adventure Time character, Finn the human.