|“||Sasha was a piece of **** before the blast, but looking at her now, is this what my powers are going to do to me? A warped body and twisted mind... is that my future?||„|
|~ Cole pondering whether he would have turned evil due to his powers after seeing how terrible Sasha has become.|
The Dark Side Will Make You Forget is the TV Tropes-popularized term about warning where turning to the dark side, either by one's own choice or corruption from outside force, is not something to be underestimated as it would made one to forget his/her true self.
A hero or other good guys may had to take a morally grey action (which decision deemed neither bad nor good) to solve his/her problems at hand, but it must be done wisely along with some consideration as they would likely lost their way in the process and unknowingly become evil until it is too late. As if losing oneself to the darkness already bad enough, dwelling in it for too long might result whatever goodness in their hearts to deteriorate to the point they eventually embraced the path of villainy and even not hesitate to cross Moral Event Horizon
A character who turned to the dark side due to ignoring this warning may be sympathetic, as they are either victim of corruption that turned them evil in the first place or possessing weak heart that vulnerable to even unexpected source of corruption like higher power/status. While they may have good intentions in committing morally questionable decisions, the longer they dwell in darkness through it, the more they forget their original dreams and goals. Those who still have redeemable qualities can be stopped before becoming full-blown irredeemable villain through their own conscience or through reasoning with his/her allies/loved ones/families, though they may still follow the dark path or chooses to turned around.
- NOTE: The examples below MUST involve characters who slowly and progressively become more and more villainous by fulfilling either or all of criteria below instead of becoming evil on a whim/instant (examples such as Ron Stoppable turned into Zorpox the Conqueror and Bloom's brainwashing into Dark Bloom won't count as they become evil in and instant and/or against their will instead through several stages of villainy):
- Frequently Choosing Bad/Selfish Choices: The hero/heroine is given clear choices over the course of his/her life, but he/she tend to choose negative ones (either in form of taking selfish choice or sought the assistance from villains) that worsened their reputation over time and unaware that he/she slowly become as worse as those whom he/she fought against. For instance, Cole MacGrath can slowly become evil the more he chooses selfish decisions.
- Willing to Follow/Succumb to Evil Influence: The hero/heroine is fully aware with the risk of malevolent corruption/negative influence that would made him/her evil, but willing to submit to it. Example: Nimue, consumed by rage and hatred towards Vortigern for killing her family, ended up killed him in cold blood in spite of Merlin's protest, resulting her corruption and transformation into Dark One.
- Lack of Strong Will to Overcome Corruption from Power/Influence They Vulnerable With: The hero/heroine is put into the situation where he/she had her psyche and conscience figuratively or literally struggled against malevolent influence that can turn him/her evil, ranging from brainwashing or corruptive substance that can corrupt both body and mind of those who touch it (which can be either scientific or supernatural in nature or both). But to make the situation relevant for this article, the hero/heroine's conscience and will to overcome the corruption would be put into a test: The hero/heroine would try his/her best to resist the corruption for a long time, but because he/she failed to rid the corruption before it's too late, he/she eventually become evil that had neither his/her friends succeed to reach for him/her, they had to put her out of her misery. The example would be Garmadon, whom eventually succumbed to corruption from Great Devourer's venom after keep it at bay for a long time, and eventually able to redeemed himself once the corruption cured through exorcism by his son Lloyd.
- Star Wars:
- Anakin Skywalker/Darth Vader: Because of Palpatine's influence that worsened his issues and failure to save his wife Padme, Anakin succumbed to the Dark Side and turned against Padme and brought downfall to the Jedi Order, becoming an icnonic Sith Lord known as Darth Vader in process. What made his case even tragic is that not only it left a lasting damage by helping the rise of the Galatic Empire, but his downfall was the testament of how hopelessly flawed the Jedi Order had became during Anakin's days as a Jedi Knight.
- Ben Solo/Kylo Ren: Being the heir of the Skywalker family and Darth Vader, Ben Solo was burdened by his family legacy. He started to hate this legacy because it created unrealistic expectations about him for both the Light and the Dark Side. To make matters worse, he was always hearing voices in his head since a very young age (which was Palpatine corrupting his mind through his creation, Snoke). Snoke would try to convince him that he was unwanted and feared by his family because of his power, which was partly true as his mother sent him away to train with his uncle for fearing that he would become like Vader, and Luke later was tempted to kill him in his sleep after sensing the darkness within him. After feeling betrayed by Luke, Ben went to Snoke as he was the last person he trusted, thus embracing the Dark Side as he also thought it was the path in which he would find his true self. However, by the time he assumed the identity of Kylo Ren, he was so consumed with hatred that he was a very different person, forgetting who he truly was.
- Nimue: As result of murdering Vortigern with her magic, Nimue has allowed herself to be corrupted by the Darkness, resulting her transformation into a Dark One as will others after her in centuries to come.
- Terra: From the moment Terra decided to join Slade so she can properly control her powers, little did she realized she became as ruthless as her mentor through overwhelming her former friends. Even so, whatever remaining compassion she had, as well as Slade's betrayal, eventually forced her to see her errors and redeem herself.
- Cassandra: After discovering that she is the daughter of Mother Gothel who abandoned her for Rapunzel, Cassandra became bitter and allowed herself to be corrupted by the Moonstone in her volition. As a result, she becomes progressively evil and vengeful.
- Heidi Turner: After rejecting Kyle and being manipulated by Cartman into staying with him and eating junk food, Heidi turns fat and becomes a bully like Cartman himself.
- Natsu Dragneel/E.N.D.: Because he was resurrected by his older brother Zeref as the ultimate Etherious, E.N.D. Natsu is doomed to suffer this fate, something that later confirmed when Lucy seemingly died on his hands. At that very point, he turned into his demon form and attacked anyone who stand between him and Zeref until is stopped by combined efforts of Erza and the recovered Lucy who used Book of Zeref, which started it all, to defeat the latter and restored Natsu back to himself.
- Lucy: As a child, Kaede (later known as “Lucy”) began to hear a voice in her head that tried to convince her to take revenge and kill the ones that betrayed or did any harm to her. This “Diclonius DNA voice” wanted Kaede to wipe out the humanity and replace them with the Diclonius race. Kaede unconsciously fell to the whims of this voice for the first time because of a group of bullies. Kaede tolerated and ignored the bullies, but when they murdered her puppy, she released her vectors (invisible telekinetic “arms” of the Diclonii) for the first time to kill them. But it was only after meeting and falling in love with Kouta, and then feeling betrayed by him, that Kaede finally surrendered herself completely to the voice. She murdered Kouta’s father and sister, then for the next years, the voice instructed her to kill people and infect human males with her vectors, so they would have Diclonius children. Thus, as a result of the misfortunes in her life, she developed hatred towards humanity and became a cold-hearted serial killer, which contrasts on how caring she was with her puppy or how happy she was beside Kouta before surrendering to the voice.
- Chirin: Because of adopting the lifestyle that mostly defy his nature as a sheep (living and training in the way of wolves) out of revenge, Chirin gradually forgot who and what he was that by the time he became more than capable to avenge his mother, he has grown into neither sheep nor wolf, but rather an abomination.
- Arthas Menethil: Due to an ignored warning about the corruptible curse within the runeblade Arthas Menethil, upon touching it, inevitably succumbed by its dark curse and became a cold and ruthless death knight he became to this day.
- Superman: Superman becomes the villain after he was manipulated by the Joker into killing his wife, Lois and destroy Metropolis, though he was once a pure hearted hero.
- Cole MacGrath: Cole becomes increasingly villainous and selfish should he frequently conduct evil actions and decisions, gradually becoming a supervillain who cares about himself. This is also an ironic instance given to his concerns upon confronting Sasha.
|“||Terenas: Ah, my son.
Arthas: You no longer have to sacrifice for your people. You no longer have to bear the weight of your crown. I've taken care of everything. (Arthas coming to Terenas)
Terenas: What is this? What are you doing, my son?
Arthas: Succeeding you, father...
|~ Arthas Menethil revealed to have succumbed to Frostmourne's malevolent curse, with end result becoming a evil, malevolent, cold and ruthless death knight.|
|“||Two years have now passed, Chirin has changed from a determined lamb, into a fearsome beast.||„|
|~ The Narrator describing Chirin's change into an abomination through adopting the lifestyle that mostly defy his nature as a sheep (living and training in the way of wolves) out of revenge.|
|“||Luke: Ben! Why didn't you tell me? You told me that Darth Vader betrayed and murdered my father.
Obi-Wan: Your father... was seduced by the Dark Side of the Force. He ceased to be the Jedi Anakin Skywalker and "became" the Sith Darth Vader. When that happened, the good man who was your father was destroyed. So, what I told you was true... from a certain point of view.
Luke: A certain point of view?
Obi-Wan: Luke, you're going to find that many of the truths we cling to depend greatly on our own point of view. Anakin was a good friend. When I first met him, your father was already a great pilot. But I was amazed how strongly the Force was with him. I took it upon myself to train him as a Jedi. I thought that I could instruct him just as well as Yoda. I was wrong.
Luke: There is still good in him.
Obi-Wan: He's more machine now than man. Twisted and evil.
|~ Luke and Obi-Wan discussing about Anakin's descent into Darth Vader and argument whether he can still be saved.|