Easily one of the most memorable antagonist pairs in Masashi Kishimoto's Naruto, Haku and Zabuza Momochi got the series off to a rollicking start in the Prologue: Land of Waves Arc, pushing Naruto, Sasuke, Sakura, and Kakashi to their limits right from the get go. In large part, this was also due to the introduction of the first kekkei genkai in the series, which was the fearsome Ice Release ability wielded by Haku. This would later pave the way for other kekkei genkai such as Wood Release, Lava Release, Magnet Release, Boil Release, and Storm Release to debut later on in the series.