Complex sentence: He hosts the Round 4 Qualifier for Akiyama and Nao's side, rooting for them, tending to fall completely for all of Akiyama's plans, even though he's not involved and knows all the rules of the game.
Split into simpler sentences: He hosts the Round 4 Qualifier for Akiyama and Nao's side. He roots for Akiyama and Nao, tending to fall completely for all of Akiyama's plans, even though he's not involved and knows all the rules of the game.