In a typical video game, you are conditioned to root for or at least care about the character you are controlling. Unlike movies, you have the opportunity to participate in their entire arc, and even help them achieve their goals. In fact, it wouldn't be a stretch to say that their goals gradually become your own. However, there are times when the most interesting character is not the one you are playing as.

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Non-playable characters (NPCs) help bring depth to the story and plot of the game. On the other hand, they can bring mysteries and plot happenings that are even more engaging than the main character. So, please sit back, relax, and take a look at our list of the ten most strangest NPCs with hidden backstories you had no idea about.

10 A Ghostly Encounter in Skyrim

Everyone knows that Skyrim has its fair share of mysterious and odd happenings, especially when it comes to NPCs. This entry reveals a mix of intrigue, an extramarital affair, and vampirism (what a combination!). In Skyrim, the main character can visit a ghost girl by the name of Helgi.

While it looks as if her father burned down the family home to be with a lover, it is instead revealed that Helgi and her mother were done away with by his mistress, Alva. Throw in a sympathetic vampire, and you have one weird and sad story — pretty par for the course for Skyrim.

9 Weird Chantings, Creepy Graffiti, and Secret Passageways...Oh My!

On the outset, Portal 2 comes across like a pretty lighthearted game. Sure, there are mysteries concerning the plot, but there isn't a lot to suggest it is harboring unsettling secrets. Well..spoiler alert..it is. In one of the game's early test chambers, you can find a room covered in weird graffiti, and if you listen close enough, you can hear odd and disturbing chanting.

Fans of the series have come to speculate that this is the work of Doug Rattmann, an NPC suffering from schizophrenia and the sole survivor of a neurotoxin attack. Much like the first entry, this is just as sad as it is scary.

8 Poor Poor Ms. Dowd

This weird NPC story comes from the acclaimed Red Dead Redemption 2. This entry is unique in that it requires you to invest a large block of time in meeting this tormented NPC character. During the night, in Bluewater Marsh, the ghost of a mysterious woman appears named Agnes.

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Her cries can be heard as you edge toward her in the swamp. So, why is she there crying? That's your job to find out. If you visit her between 9 PM and 3 AM 16 times you can see the horror story that led to her spending the rest of her days in a swamp.

7 The Curious Case Of Nick Valentine

Considering what happens in the Fallout series, a robotic NPC detective is probably one of the least weird things to come out of this game. However, Nick Valentine's story is one for the ages. He is a synth-based detective that has unparalleled investigative skills, is adept at melee, has human-like intelligence, and has pre-War memories.

Why? Well, Mr. Valentine was initially a real person whose brain was scanned as a part of his PTSD treatment. In an even weirder turn of events, Valentine used to also be a detective in his former life. This guy's story is filled with equal parts intrigue and insanity.

6 The Return Of Eddie Low?

If you are new to Grand Theft Auto, or only played the fifth installment, you may have wondered why trucker, Eddie Low was refused by a security guard. Well, there is a reason for that. This backstory is less about Grand Theft Auto V's Eddie Low and more about the video game's fourth installment of a similarly-named character.

This name also belongs to the fourth game's infamous serial killer. Abused as a child, Low went on to murder his father, brother, and mother before he began his murderous spree in Liberty City. No wonder GTA V's Low wanted to immediately "clarify" the connection to all who asked.

5 The Truth - Everyone's Favorite Hippie

In Grand Theft Auto: San Andreas, the main character, CJ interacts with a man named The Truth. This guy is involved in a few missions within the game and drives a pretty psychedelic camper. However, who is this guy? Well, if you guessed conspiracy theorist and believer in alien life, you would be correct.

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The Truth has called into the Area 53 radio station claiming to have interacted with alien life and is even speculated to have an account on Grand Theft Auto IV's whattheydonotwantyoutoknow.com under the name Trooth. While he may come across as a throwaway NPC, this guys journey from pure hippie to a conspiracy theorist is worth a look.

4 The Enigmatic Merchant

Xur is a mysterious merchant that seems to show up at the right time when you need rare items in Destiny or Destiny 2. However, who is Xur? Do you know who you are buying things from? Well, for starters, this guy is endlessly loyal to The Nine, rulers of the Jovians.

In his past, Xur was basically in the wrong place at the wrong time and got caught up in the disappearance of the Queen Reef's lover, something that was likely the fault of The Nine. His result: a hammer to the chest and a resulting long-term injury. Talk about loyalty. No wonder this guy is so enigmatic.

3 A Brain Clone

Nick Valentine isn't the only robotic "clone." The Halo series also has the intelligent and highly capable Cortana. She serves as the game's pivotal AI figure and a partner to John 117. However, she didn't just appear out of thin air. Her story is as captivating as you would expect for an AI the caliber of Cortana.

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She was created as a clone from a copy of a doctor's (Dr. Catherine Halsey to be exact) brain. She is one of only two AI to have been created from Haley's mind. Halsey realized Cortana was a bit "abnormal" when the robot removed her termination code. Makes perfect sense Windows would want to name software after this character.

2 Everything Isn't Always What It Seems

Ryo stands in the middle of a busy outdoor shopping mall

Shenmue is one of the Sega Dreamcast's most shining titles. Unfortunately, controversy surrounds the remake. However, it is worth remembering how masterful the original was. One of the most exciting aspects was the game's use of NPCs. Citizens were seemingly going about their day as you guide the title character through the in-game world.

Sadly, all is not well with each NPC citizen. Yoshikazu Takahashi walks up and down the street each day. However, while the guy looks reasonable enough, his backstory reveals that his company went bankrupt and he gets up every day with a suit and necktie to try to muster the courage to tell his family. YIKES!

1 A Disgruntled Pet Led To A Franchise

While Donkey Kong has had his own outings for the past two decades, the notable gorilla has not always been playable. In fact, video game vets will recognize that Mario of Super Mario fame made his first famous outing in the first Donkey Kong game.

It may seem from the outset that Mario is the good guy as he is on his way to save his girlfriend. However, it is revealed that Donkey Kong stole the girlfriend as revenge for Mario abusing him. We can thank Mario's animal mistreatment for turning an NPC into one of the most popular video game characters of all time.

NEXT: Donkey Kong: The 5 Best Games in the Franchise (& The Five Worst)