He is well aware of Gamu's true identity as Gaia but kept it to himself until XIG's migration to Geo Base after Mokian's assault.
Charija kidnapped the monster in the middle of its fight with Night Raider operatives and upon deployment, it begins fighting Ultraman Gaia.
That perception being that Tokusatsu can only tell really hotblooded and highly emotional tales with giant personalities that lacked levels of depth and nuance.
Agul and Gaia finally team up and, together, defeat the monsters.
Despite his excellence in the scientific field, Gamu is shown to be weak in terms of physical fitness and eventually trains harder as the series progresses to keep up Gaia's performance.
Gaia, his ColorTimer blinking, changes back to Gamu, and thanks the young boy.