Ryusei couldn't say it was entirely his fault, though he wouldn't be able to deny anything if anyone asked.
In his defense, the Itoshi's seemed to be all cut by the same blade. It drove him crazy in different ways.
Rin Itoshi made him mad; blood rushing through his veins whenever he argued with the boy. Sae Itoshi got his senses overwhelmed, his play in the field went through the roof after when playing with him. And you... sincerely, he hadn't even known there were more Itoshi's. But you had another kind of effect on him outside of football.
You had him a fool the second his eyes met yours. He'd seen those teals eyes plenty of times in Sae and Rin, but there was something in yours that just made his skin tingly and for a certain warmth to settle in his chest, constricting his ribcage as it flooded his insides until it reached his heart. A fleeting moment really; a few seconds were more than enough to have your hooks and claws gripping his wildly beating heart in your hands. You probably didn't even knew it. But God, did his mind wandered.
He knew your name in passing, barely a whisper that had still been burned in his brain; and it just seemed to fuel another kind of storm inside him. He wondered how your voice would sound like, how your skin would feel like under his fingertips, what you liked and what you despised, how it would feel to come home to you. He wanted to know everything, from the obvious things to the things that only one intimately close person would know.
He was gone; and by all means, he didn't minded falling deeper into the rabbit hole.