Bloom
Because more than anything else, Reborn knows foolishness when he sees it. He knows that foolishness has a tendency to bloom in any season and he knows its best to pick its ripe fruit with the tender hand of a green-thumbed octogenarian. But he is only 3 feet tall, when measured with a generous ruler, and whilst the harvest awaits, gleaming in the shift-season sun, he is still a seedling under it's stream.
When Yamamoto turns 15, Reborn is 3. When Yamamoto turns 16, Reborn is 3. When Yamamoto turns 17, Reborn is 3.
When Yamamoto thought he was in love with Gokudera, Reborn is 3. When Yamamoto thought he was in love with Hibari, Reborn is 3. When Yamamoto finds himself proven wrong on both accounts, Reborn is 3.
When Yamamato is 17 he kills his first man, split seconds later, he kills his second, third, a minute later he kills his fourth, fifth, Reborn is 3.
After all this, he still plays baseball. He dreams of moving to Tokyo, away from Namimori (Tsuna, Gokudera, Hibari, Mediocrity, Failure) playing in the major leagues. He still laughs and they are full, deep from within and musical in the way that a rooster crows in the morning was an orchestral delight. He dreams of falling in love. Reborn is 3, and only he knows this. So he begins one-on-one training with Yamamoto once more. Tsuyoshi has come to represent what Yamamoto was afraid of, the prospect of glory replaced with the prospect of waking at 3:30 every morning with the only promised adrenaline rush coming at the time of the tuna auctions. Reborn knows what drives Yamamoto and that is the simplicity of the unattainable. Reborn knew a lot of things, his role especially well.
At the crest of Yamamoto's youth, final exams and university entrances looming, the junior league finals less than a fortnight away, scouts from Tokyo dropping by almost every week and the oncoming return of Tsuna, Hibari and Mukuro from a 7 week long mission of utmost secrecy, he turned 17, 5 months, 18 days, 13 hours and give or take 22 minutes. Arbitrary, perhaps.
Reborn turned 22.
He came home later that night, the coach was pushing the team harder than ever and he really wasn't complaining. His heartrate would stay elevated for the rest of the night and the tingling in his arms would refuse to leave, this he could foresee. There was a pain in all the muscles of his legs which he could only describe as amazing and his eyes had a manic gleam. Yamamoto was still in full uniform, hat, long socks and dusty bat when he met Reborn for the first time, seated around his father's sushi counter with the rest of the Vongola Familia. Reborn tipped his hat, Yamamoto grinned.