Alfin is a Rain-attribute Box Weapon with its whole body clad in Rain Flames similar to water. Its design is unique even among the Box Weapons left by Lorenzini and is considered a prototype Box Weapon furnished with an advanced communication system. Basil acquired it along with his Ring and the Book of Sukedachi in Spain after being sent ten years in the Future.
AbilitiesThe intelligence of the Rain Dolphin is high and it is capable achieving of mutual understanding of intention with most Animal Box Weapons.
- Dolphin Edge: Rain-attribute Flames are gathered on Alfin's fins and are then shot forward like edged projectile Weapons. Since these Weapons are infused with Rain Flames, they can act like tranquilizers by soothing the enemy.
- Telepathy: Alfin can respond to telepathic commands from Basil.
- Brain Coating (Inter-Box Combination Launch System): Due to the high intelligence level of the Delfino di Pioggia, Alfin has the Ability to interconnect with other Box Animals, including the Vongola Box Weapons. This synchronization allows the Animals to launch a synchronized and secret attack.
- Super Nova Ocean: This attack, combining Alfin's power along with the other Boxes, was used to crack the barrier shutting off Tsuna and Byakuran's fight, letting Gamma slip through.
- Taienrankuga (Flame Storm Sky Fangs): A combined Attack with Kangaryu and Uri. Kangaryu shoots Uri with a Sun Bullet that increases its size and strength instantly, while Alfin combines its Rain Flame with Uri's Storm Flame. This results in a deadly Flame combination.
- Alfin's Box is marked "CEDEF," the organization that Basil belongs to.
- Alfin and Basil have fought the Millefiore forces approximately 8 times in the 10 days that it took Basil to reach the Namimori HQ. These battles all took place before they were introduced in the Future Arc.
- Alfin's brain is shown to be coated with Rain Flames.