The truth is revealed to Mai on Kamen Rider Gaim Episode 26: Baron’s Genesis Henshin.
Episode 26: Baron’s Genesis Henshin
Writers: Gen Urobuchi and Jin Haganeya
Director: Satoshi Morota
Kōta’s suspicious attitude gets the best of him and Mai finally demands to know if he’s hiding something. Unable to keep it a secret anymore, Kōta reveals to her that Yuya had become an Inves and it was Kōta himself who eliminated him.
In order to save humanity from the Helheim invasion, their number has to be reduced to 1 billion*. Even if it meant saving the species, Takatora was deeply anguished by the thought. Mitsuzane, on his part, unleashes his anger at Kōta for having revealed the truth to Mai.
Mai now tries to let anyone who will listen know that Helheim will destroy humanity and Earth, however, Mitsuzane’s skillfull Inves summoning foils her plan.
“You shouldn’t have involved Mai in this, Kōta!”
Mitsuzane, having made a decision, approaches Ryoma and tells him about a plan. What could this plan be?
All English translations are accredited to The Tokusatsu Network staff members. Please do not repost without crediting and directly linking back to the original Tokusatsu Network article.
*Thank you to Tyler, for the translation correction.