Ken Masters is a fighter from USA whom was sent by his
father to master Gouken. There he trained under his Gouken along with Ryu under a fighting style called Ansatsuken. Ken's primary focus is on the Shoryuu principle which is why his Shoryuken move is characterized with flame while Ryu follows the Hadou principle.
The difference between the Ansatsuken twins is mainly in their moves. Ken has a stronger Shoryuken and multi-hitting Tatsumaki Senpuukyaku(Hurricane
Kick) while Ryu as a
single hit knockdown Hurricane
kick and a stronger and faster Hadoken.