In "Fist of the North Star" (Hokuto no Ken), Hyoh (or Raoh) does not use the same style as Kenshiro, but they are both practitioners of the Hokuto Shinken martial arts school. Kenshiro is the main protagonist and inheritor of Hokuto Shinken, while Hyoh (or Raoh, depending on the era you are referring to) is a powerful antagonist who also possesses the skills of Hokuto Shinken but applies them differently, often emphasizing brute strength and a more ruthless fighting style.
While their techniques and principles stem from the same martial arts lineage, their philosophies and approaches to combat highlight their character differences. Kenshiro values justice and protecting the weak, while Hyoh/Raoh embodies a more tyrannical and power-driven ideology.