Riku is a central character in the Kingdom Hearts series, known for being the best friend of the protagonist, Sora. He is a brave and strong-willed individual, often struggling between the forces of light and darkness within him. Throughout the series, Riku's character development is marked by his quest for power and redemption. He begins as a rival to Sora but eventually becomes a key ally, demonstrating his growth and maturity. Riku's journey is integral to the overarching narrative, as he plays a crucial role in the battle against the Heartless and other antagonistic forces.