When he was young, he, along with Kaiou team were confronted by Tsurugi and were humilated by him. Some time later Kuroki Zenzou appears, calling the team to train under Fifth Sector's supervision. A few years later, as a forward and captain of Kaiou, Namikawa plays against Raimon in Kanto preliminaries. He is a SEED who has the Kaiou Poseidon keshin/avatar in his possesion. He scored the second goal against Raimon, but at the end, his keshin/avatar was easily overpowered by Tenma's keshin/avatar resulting in Kaiou's loss with a score of 3-4.