Terra is a key character in the Kingdom Hearts series, serving as one of the main protagonists in Kingdom Hearts: Birth by Sleep. He is a Keyblade Master-in-training alongside his friends Aqua and Ventus. Terra is known for his strength and determination, but he struggles with the darkness within him, which ultimately leads him to be manipulated by Master Xehanort. His journey and internal conflict are central to the series' narrative, as they explore themes of friendship, identity, and the battle between light and darkness.