Swomboi vaguley represents a pheonix, due to his bird-like appearance and Fire Element abilities. The crest on his head also is vaguley similar to the fire Head of the Okami Character Orochi. To finish similarites, his wings also are similar to Reshiram's.
Swomboi is a more playful member of the Nightmare team. However he does have a dark habit. Since he lives in a dormant volcano nearby a city, he requires the people to sacrifice their crops to him. If they don't he will reactivate the volcano and wipe out the entire city. Because of this, the people are barely feeding everyone.
When around his brothers Swomboi is usually the one chosen last to perform certain tasks. This is because he is considerably weaker than the others. He usually prefers to stay in his own home and heighten his own power.
The first appearance of Swomboi was in Episodes 5 and 6 of GALAXY. There, he was only a hatchling and hiding in secret from the main population. He lived in the volcano near Kazan town.