"Holy Emperor" Souther is the only master of Nanto Houou Ken (South Star Phoenix Style), the strongest style among all variations of Nanto Seiken. Thus, he is one of the strongest fighters in all of Hokuto no Ken.

Nanto Houou Ken is characterized like the other Nanto Seiken styles with sharp slicing movements designed to damage the external body, but unlike the others Nanto Houou Ken has no rigid stances or movements, save for one. When confronted with a worthy opponent, Souther unleashes his ultimate technique,　Nanto Houou Ken Ougi: Tenshou Juuji Hou (South Star Phoenix Fist Ultimate Technique: Soaring Cross Phoenix)

Because there can only be one Nanto Houou Ken master in any given time, Souther was forced to kill his mentor and beloved foster father, leaving him bitter, angry and declaring that he has rejected the concept of love forever. He constructs the Holy Cross Pyramid using child slave labor as a monument to his father. With its completion, he intends to bury his emotions forever.

"I am the Holy Emperor Souther, Emperor of the Six Sacred Fists of the South Star! No retreat! No mercy! No hesitation!"

(Source: Hokuto no Ken manga Volume 11)