Who would you consider the primary antagonist of each DR season?

Before Dragons Rising it felt as though there was always a clearly defined ‘main villain’ Dragons Rising feels different where you’d probably have a few good cases for main antagonists probably due to the seasons being in parts. Just wanted to see what other people thought I personally consider Beatrix to be season 1’s main antagonist, Ras to be season 2’s (though it could be argued the forbidden five are? Or maybe Bleckt) and Thunderfang to be season 3’s as the Five feel far more like elite...