The first installment in the Naruto series quickly established some significant threats, be it Zabuza on the bridge or Gaara’s sociopathic era during the Chunin Exam arc. However, at this point, there was no greater evil in Naruto than Orochimaru. He’s the series’ first major antagonist and arguably manages to get away with so much in such a short amount of time. He gives the series one of its earliest tragic deaths by killing the Third Hokage, Hiruzen Sarutobi, in the episode “Beyond the Limit of Darkness and Light” (via Crunchyroll). What makes the victory particularly difficult to swallow is that if Sarutobi had had more power, he could have sealed Orochimaru’s soul and stopped him altogether. Instead, Orochimaru leaves a hole in the heart of Konoha and later snatches another worthy victory with one of the village’s own.
Orochimaru is able to get Sasuke to follow him and it all starts with episode 30 of the series when he leaves Sasuke with the curse mark. The mark grants its user greater power at the cost of their sanity. And Orochimaru’s whole goal was to use it to possess Sasuke’s body. However, the move brings the villain several unforeseen victories. In particular, it plays a role in Sasuke’s quest for more power at any cost, leading to him abandoning his friends and village. Young Uchiha continues his dark path well into Shippuden and even manages to become a wanted criminal. Orochimaru couldn’t foresee Sasuke’s path, but he certainly didn’t complain as it pitted him against former friends and teachers.