Strea

Strea (ストレア) is a playable character in Sword Art Online: Infinity Moment.

Sword Art Online: Infinity Moment
She starts tailing Kirito after the events of 75th Floor boss room. She does it without him noticing, even with his high level detection skill. But, although his skill detects nothing, he can feel her presence and eventually forces her to reveal herself. Strea greets him with a smile and introduces herself, but doesn't tell Kirito the reason why she was tailing him.