Brontos is introduced in Kid Icarus:The Scientist. Brontos was the mastermind behind the Aurum to get rid of Pit so he could be the ruler of Skyworld. He is very difficult to defeat since he can create whatever he wants to destroy Pit.
Dyntos and Brontos are twins so they look a lot alike. Brontos carries a giant pickaxe instead of a hammer like his brother carried. Also, Brontos' pickaxe has green fire shooting out of it, but Dyntos' hammer has blue fire shooting out of it.