"It's Momo Sagara☆Nice to meet you-nyan"
- —Momoka, Valkyrie Drive Mermaid
Momoka Sagara is a mysterious girl who was transferred to the "Mermaid" island later on, other than Mamori and Mirei. She awakened as an Extar already during the bird's arrival and her abilities are quite high. She is cruel to the pure ones due to her wild personality, who is not scared of anything. She often bears a discord with others by their behaviour and disturbs her surroundings.
Momoka has light-blueish hair that is tied in a bow with two long pieces of hair flowing out reaching almost to the ground. She has a cat hair clip similar to Mamori's clipped at her bangs. She has turquoise eyes.
She wears a black bluish jacket with a yellow bow wrapped around her collar. To accompany it she wears a short skirt black-blue boots, a black glove on her right hand and a stocking on her left leg.
- She was Mirei's previous Extar.
- As seen in episode 8 she can enter drive with anyone.
- She is a third generation Soldier Arm Extar.
- She belongs to an unknown organization sent to the Island Mermaid for a mission to retrieve the girl (Mamori) who generated the Valkyrie Effect seen in Episode 8.
- Momoka's code name is A3.