Sun and Son

"And what if we sealed them?" Iemitsu offered, sounding a mix of desperate and hopeful. Timoteo understood why. The man didn't want his family to get involved in the mafia and the ability to use flames was like a dead giveaway of such involvement- not the mention the danger the flames themselves could pose to the child.

Still, he shook his head.

"We can't just seal his flames, Iemitsu; it would cripple him," he finally said. "The best solution would be to teach Tsunayoshi-kun how to control them."

Or, the one where Timoteo doesn't seal Tsuna's flames and instead Tsuna becomes Reborn's student a few years too early.