Baihumon is the Sovereign of the west. He is a Mega level, and is the most powerful Sovereign.
He resembles a white tiger with a white aura.
Baihumon was first seen fighting the D-Reaper in a crevice. The D-Reaper beat him up, injuring him, but nonfatally. Cyberdramon had initially intended to fight him, but decided that he needed to fight the D-Reaper instead. He and Ebonwumon later went over to the edge of the pit where Azulongmon, Zhuqiaomon, and the tamers were.
Baihumon fought alongside the other Sovereign and Mega Digimon against the D-Reaper. The four Sovereign survived the battle, pulling Cable Reaper through a portal to the digital world enabling the final defeat of the D-Reaper.