Katekyou Hitman Reborn!

Synopsis

Yuni explains that like the Mare ring's ability to allow its user to travel through parallel worlds, the Vongola rings allow the past generation to communicate with their current successors. Vongola Primo converses with Tsuna, revealing the rings had a seal on them, allowing them to be split in half for the Vongola Tournament and their current forms only possess powers equal to the Mare ring. Primo releases the seal causing the Vongola Rings to change forms and disappears. Tsuna continues his battle with Byakuran, overwhelming him completely. As Yuni nearly completes the rite, Gamma manages to infiltrate the barrier and embraces her; exclaiming he will die with her. As the rite completes, their bodies disappear leaving behind the Arcobaleno pacifiers. Tsuna and Byakuran's battle climax with Byakuran perishing from Tsuna's X-Burner.

(Source: Wikipedia)