Sounds pretty classical in power-metal genre. But it's not that heavy. I neither can hear something new nor heavy in their compositions , which haven't already been implemented in European countries. But it's cool that there is something in Brazil. These groups are not very popular.
The last one is great. I collect folk-around songs. And I love power-metal actually. Because of the great vocalist's work. It is not so bright and clear in black-metal (ofc) or in a popular nowadays melodic-death-metal.
The heaviest metal I've ever listened to is Therion's one. Genre is symphonic-metal, today is progressive-metal.
Well, I'm not a metal-fan, I love eclectic jazz, avantgarde metal, concrete electronics, ethnic music, etc.