Onismon

Onismon is a Mega Level Ancient Bird Digimon. It is also known as Ornithmon.

Digivolution
Onismon's normal Digivolution in Digimon Adventure:
 * Fresh - Nyokimon
 * In-training - Yokomon
 * Rookie - Biyomon
 * Champion - Birdramon
 * Ultimate - Garudamon
 * Mega (Ultimate) -Onismon

Attacks

 * Cosmic Ray: Fires a black lightning from his mouth.
 * Tempest

Island of Lost Digimon
Onismon is an ancient Digimon who was sealed away by AncientGreymon and AncientGarurumon in ancient times when he terrorised the Digital World. When the villainous Murmuxmon heard of him, he planned on reviving him to get revenge on the ones who banished him to the Wandering Island. To do so, Murmuxmon unleashed a war between the human form and beast form Digimon on the island to get many Digieggs which would help him revive Onismon. Although the DigiDestined found out what he planned, it was too late and Murmuxmon was able to revive Onismon. The two then went on a killing spree on the wandering island but the DigiDestined as well as the tanks of both factions were able to cause some damage to the powerful Digimon. Bearmon's prayers finally allowed AncientGreymon and AncientGarurumon to appear and they destroyed Onismon, this time for good.