Orochimaru was an incredibly powerful character in the Naruto world. Introduced quite early into the series during the Chunin exams arc, Orochimaru appeared as a villain who had nothing but malice in his heart. He took part in the exams to find a suitable vessel for his body to transfer himself into, in order to gain even greater strength as a Shinobi.
During his introduction, Orochimaru was quite clearly the greatest villain the series had seen at that point. His aura was threatening and even the likes of the Hokage were wary of his presence. At his best, Orochimaru would have been an unstoppable villain in the Naruto series. However, moving on in the story, circumstances changed and he became irrelevant as a character for several reasons.
Orochimaru's Rise To Power
Orochimaru was born a genius. By the age of six, he was already a Chunin of Konohagakure and had mastered several jutsu. Having lost his parents and a very young age, his goal in life was to learn more about its meaning and eventually this led him to finding ways to attain immortality. Being the most skilled ninja of his time in the village, Orochimaru received great praise and earned the respect of the likes of Hiruzen Sarutobi, who consider them to be his favorite student. With time, Orochimaru became a Jonin and, at the same time, made great progress on his hunt for immortality as well.
Sadly, he also had a twisted mind and would go to any lengths to attain his dream. Orochimaru went on to fight in the Second Great Ninja War and became one of the Legendary Sannin of his village. Earning legendary praise, Orochimaru quickly became a candidate for the position of Hokage as well. Unfortunately, his evil ways had grown significantly at this point and he would even kidnap people and experiment on them for the purpose of attaining immortality. This is when he hit his peak as a fighter and, eventually, defected from the village once found out.
Orochimaru's Prime
As a Shinobi, Orochimaru was tremendously powerful. Even Kakashi Hatake, a ninja worthy of becoming the Hokage, couldn't help but get paralyzed by fear in his presence. Orochimaru was powerful enough to master all five Nature Transformations at a very early age. At the same time, he mastered countless jutsu, some of which are exclusive to him. Just like his teacher, Hiruzen Sarutobi, Orochimaru knew nearly every Jutsu in Konoha's existence. His prowess in combat was such that he could even kill the likes of the Fourth Kazekage with ease. Furthermore, he even went on to clash evenly against Hiruzen Sarutobi during Konoha Crush. Sadly, Orochimaru's body did not allow him to fight to the best of his capabilities. His sickening body meant that he could not use Sage Jutsu at all.
Having found Ryuchi Cave, Orochimaru had managed to learn the ways of Senjutsu as well. Sadly, he didn't attain the body to put this into practice. Instead, he ended up creating the Cursed Seals. In his prime, he was certainly a menacing fighter and could take on the likes of Jiraiya and even Kage-level Shinobi with ease. Unfortunately, his body never allowed him to reach his maximum potential as a fighter.
Orochimaru's Fall As A Villain
Orochimaru was quite easily one of the most compelling villains written by Kishimoto in early Naruto. Perhaps, the most intriguing thing about his character was the threatening aura that he emanated. In the first part of Naruto, until the timeskip, Orochimaru was quite easily one of the greatest villains in the entire story. As the story started to focus more on the Uchiha clan and the tale of Indra and Ashura, characters like Orochimaru ended up becoming less relevant. In fact, Orochimaru ended up getting killed off quite early into the second part of the story which was very anticlimactic, to say the least. His remains were then absorbed by Kabuto, who ended up becoming one of the perpetrators of the Fourth Great Ninja War.
In the war, Orochimaru returned once again, thanks to Sasuke, the man who killed him in the first place. Despite returning, it was evident that Sasuke, along with many other Shinobi at the time, had already surpassed Orochimaru. His character was no longer menacing and he was never given a proper arc to demonstrate his true abilities after Konoha Crush. What's even worse, Orochimaru was treated like a gag character in the war and despite all his wrongdoings, he was, apparently, forgiven and even allowed to have relationships with the Leaf Village. Orochimaru, much like many other villains in the story, ended up becoming "good at heart" and all his potential as a terrific villain was destroyed.