Ugetsu Asari

Title: Vongola First Rain Guardian
Gender: Male
Weapon: Ugetsu Asari's Four Irregular Swords
Flame: Rain

The First Rain Guardian Asari Ugetsu, was Japanese, and loved music. It was said that there were none who could match his skills with the blade. He physically resembled Yamamoto, and Reborn compared Yamamoto giving up baseball to the first Rain Guardian giving up music: both did so to excel at swordsmanship for the sake of their friends in the Vongola Family. Specifically, the First Rain Guardian sold his instruments for a trio of short swords and a single long sword. Yamamoto's Kojirou can Cambio Forma into a similar sword, called Asari Ugetsu.

Weapons and Abilities
Asari Ugetsu : Asari Ugetsu are one long blade and three short swords. It was said that the First Rain Guardian replaced his musical instruments with a similar weapon in order to help the Vongola in a time of crisis.

(Source: Reborn Wikia)