I still find it funny how all the "final boss" brawlers were all either aligned with the pyrus or darkus attributes.
Battle Brawlers:
Masquerade & Hydranoid - Darkus
I guess Naga is an exception to that since he wasn't technically aligned with any of the core attributes but his Silent Naga variant seems to lean more towards darkus than any of the other attributes.
New Vestroia:
Spectra & Helios - Pyrus
King Zenoheld & Farbros - Pyrus
Honorable mention to Prince Hydron who was a subterra brawler. However while he was technically one of the main antagonists of the first half of the season, he wasn't actually a brawler until the second half, at which point Zenoheld had already been established as the "final boss".
Additionally, Spectra & Helios switch attribute alignment during a later season but since the switch is to the darkus attribute (and at that point in the series they're no longer enemies) so they're still eligible for this list.
Gundalian Invaders:
Ren Krawler & Linehalt - Darkus
Barodius & Dharak - Darkus
Mechtanium Surge:
Mag Mel & Razenoid - Darkus
Betadron - Darkus
I didn't list Wiseman because he uses all of the Nonet Bakugan which means he wasn't just restricted to one attribute.
There wasn't really any point to this, just a funny little detail. It would've been interesting to see some other attribute as the "final boss" brawler & bakugan duo but I'm fairly happy with the ones we did get.
