Fans love to see heroes pushed into uncomfortable positions. When a protagonist with strong moral fiber is asked to pretend to be evil for information, to acquire something from the true villains, or to kill someone they otherwise couldn't reach, they have to decide what part of their code they can compromise on to be convincing.
For certain heroes, the act of pretending to change sides comes naturally and they're even able to convince their own allies they've betrayed everything they once believed in. Others are better off not trying, because they're simply too good to pull off a turn to villainy.
10 Chris Yukine Worked With The Villains To Retrieve Solomon's Cane (Symphogear)
When Chris is introduced into the Symphogear universe, she starts out as a villain. Wielding a new armor no one's seen before, the gun-crazy teen has no problem fighting both Hibiki and Tsubasa. But eventually she decides to change sides, joining up with the other girls to defeat Fine. In season two, though, she briefly pretends to be a villain again for the sake of trying to recover the Solomon's Cane relic.
9 Piccolo Faked Being Evil To Get The Cure To The Black Water Mist (Dragon Ball)
Piccolo actually was a villain for a while. The character was introduced as the son of King Piccolo and spent the first three years of his life planning to take Goku down. But by the time the Frieza Saga ends, Piccolo is firmly on the side of the good guys. Still, during the Garlic Jr. filler arc, Piccolo was bitten by one of Garlic Jr.’s soldiers and spent most of the arc pretending to be evil until he could find the right time to take Garlic out.
8 Krillin Worked With Piccolo To Retrieve The Black Water Mist (Dragon Ball)
Alongside Maron and Gohan, Krillin was one of the only people who managed to escape the Black Water Mist. They head to Kami's Lookout where they run into Piccolo, who pretends to be affected by the Black Water Mist. Eventually, Piccolo also "bites" Krillin, who then pretends to be affected by the Mist and made into one of Garlic Jr.’s slaves.
Once Garlic Jr. lets his guard down, both Krillin and Piccolo reveal they were never affected by the Mist at all.
7 Hawks Joined The League of Villains To Help The Heroes Reach Their Goals Swiftly (My Hero Academia)
Hawks is assigned to infiltrate the League of Villains in the later seasons of My Hero Academia. Unlike most cases, this is an instance where the viewers know the character is still a good guy from the beginning — at least, the ones not coming up with weird theories. Hawks' goal is to make a world where there's peace as quickly as possible, and to that end, he's willing to do anything.
He joins the League, which works out in everyone’s favor; with his intel, the heroes are able to move fast enough to stop the villains. Still, his victory didn't come without feeling as if he'd betrayed a piece of himself.
6 Laxus Dreyar Wanted To Become Evil But Couldn't Convince Himself (Fairy Tail)
Laxus is a weird example of a hero pretending to be a villain because he actually wanted to be a villain. He made a legitimate attempt to take over Fairy Tail, or so he thought. He turned all the women to stone and tried to convince everyone who was "weak" to get out of the guild.
But at the end of that storyline, it's explained he was never really trying, which is why when he attacked Magnolia with Fairy Law, he couldn’t hurt anyone. He simply didn't see any of them as his enemies. This also explains why he wasn’t able to defeat Natsu, someone who he was pretty much always able to easily defeat before.
5 Gin Ichimaru Spent Centuries Working For Aizen Until The Right Moment Came Along (Bleach)
Gin looks so untrustworthy that even when he's revealed as a villain, no one's particularly surprised by it. However, the double-cross was that Gin was actually against Aizen and his plans the entire time. He remained by Aizen's side for centuries just waiting for the chance to betray him.
His goal? Revenge for Aizen stealing part of Rangiku’s soul to create the Hogyoku. Gin turned on Aizen right after he'd achieved his goal, which unfortunately turned out to be too late. By then, Aizen was far too powerful to be stopped by Gin.
4 Gajeel Worked For The Rival Guild Raven Tail As A Double Agent (Fairy Tail)
Gajeel frequently pretends to be villainous, presumably because he has the look of a dastardly villain. The character starts off as a member of Phantom Lord, but joins Fairy Tail shortly after that group's defeat.
Not long afterwards, the character reveals that he’s actually a member of Raven Tail, a guild started by Makarov's son, and he's been spying on Fairy Tail for them. But that turns out to be a double-cross with Makarov having asked him to spy on Raven Tail for the sake of learning what his son has been doing.
3 Uryu Ishida Joined Up With The Quincy For Revenge (Bleach)
The Quincy were the natural enemies of both the Soul Society and the Soul Reapers because they upset the natural balance of everything by killing Hollows instead of allowing them to be reborn. Though Uryu changes sides to work with Ichigo, his loyalty is called into question during The Thousand Year War arc.
There, Uryu joins up with Yhwach, the father of the Quincy. He even gets in the way of Ichigo and his other friends when they try to stop Yhwach from reaching his goals. Still, in the end it was all a ruse and Uryu came back to the side of the good guys in time to help them fight Yhwach.
2 Gray Fullbuster Joined The Dark Guild Avatar Just To Take Them Down (Fairy Tail)
Gray Fullbuster was Natsu’s rival for much of the series, but after the Tartaros arc, he became more than that. Suddenly, the character took on the powers of his father, turning him into an Ice Devil Slayer. Though it came with a massive power boost, it also meant the character was more likely to become evil. During the year-long time skip, Gray joined up with the dark guild Avatar, abandoning Juvia, though the whole time he was only looking to shut them down.
1 Itachi Uchiha Pretended To Be Evil For The Sake Of Konoha And His Brother (Naruto)
Itachi is possibly the most well-known example of an anime hero pretending to be a villain. The character starts out as his younger brother Sasuke's mortal enemy for wiping out the Uchiha clan. Itachi even demands Sasuke use his hatred to propel him and make himself stronger. In the end, though, it's revealed that Itachi was the only Uchiha member loyal to Konoha, and he only killed the others to keep his younger brother safe.