|Not to be confused with her own rock band.|
In her debut episode in the SMG4 universe, she comes to life when Fishy Boopkins uses Kamek's wand to make her come out of his dating sim, but in real life, she becomes extremely jealous, destroying anything that might get between her and Boopkins, even his waifu body pillows, which she ignites with fire. This, of course, leads to Boopkins dumping her, and her going insane, plotting revenge on him and the main protagonists. She is later stopped and both her and Boopkins are forced to let go.
Saiko tried to attempt to defeat SMG4 and Mario with her Minigun Machine she was lucky to acquire. When Fishy Boopkins was about to fall, it is revealed that she still has feelings for him and wanted him back, as she tries to save him from falling off a cliff; although she appears to have gone tsundere since her debut. Unfortunately, Mario kicked her down the cliff with Boopkins.
Saiko makes the antagonist again in the episode as the Commander of the Militia Base. As Meggy had not met Saiko previously, Mario and SMG4 are forced to explain to her that she used to be Boopkins’ ex-girlfriend and that she’s crazy. She states that her goals are to rid the world of pretty people, allowing her to become the prettiest person in the world.
Mario then diagnoses that Saiko has Schizophrenia. Retorting that she is not crazy, but heartbroken, she orders a squad of Cactite to rid of the party. SMG4 uses magic to summon walls to block off any damage. Now surrounded, Meggy comes up with a plan. She tells Mario to use his Buster Sword to send herself airborne just above the wall so she can shoot down the Cactite. Saiko, now very unsatisfied, pulls out a UNSC Asymmetrical Recoiless Carbine-920 (Also known as a Railgun to fans of the Halo Series of games.) and destroys the wall surrounding the party. Everyone, now on the ground, she tells them to run back home, then fires more lasers on the team. Mario tries to dodge the oncoming fire but is knocked backed, SMG4 and Meggy try to counteract by throwing their inventory at Saiko, who can dodge anything they throw.
Mario then reappears by flanking her right and makes her go airborne and drops her. SMG4 demands that she gives up. But it appears that Saiko hasn’t finished; she whistles up a flying mech as everyone stares in bewilderment and confusion. The Commander says it's time to end this. SMG4 retaliates by throwing fire; it does absolutely nothing. Saiko finds this quite cute, then fires Banzai Bullet Bills. Mario tells her off but is blasted once again. SMG4 erects a glacier to protect himself and Meggy, who comes up with another plan. With the help of SMG4 and Mario, she makes a Banzai Bill flip and hit the flying mech, causing it to explode. An unconscious Saiko is last seen being thrown through a portal by Mario.
In this episode, she appears in a park after being called by Mario. When she got there, Mario tells her that he's doing a TV show and needs her to be a part of it, which she was excited about since she thought he needed a model. However, Mario reveals she is part of his next challenge where he turns the turret on which would fire at her. Later in the video, she and the others get revenge on Mario with the same stunts pulled on them, as she was waiting for him in a bunker with a sentry who fired at Mario. At the end of the video, she asks Mario if he has anything to say to people he pranked, attempting to make the plumber apologize, but he then said: "Eat my Mario Pingas" to which she makes the sentry fire at him again.
In this episode, she is seen tired of being feared by everyone because of her behavior and Luigi tries to teach her to be nice but fails to do so. Later, Saiko tries to give something good to the characters she hates the most. Bob doesn't like Saiko at all. He has received a chocolate ice cream from Saiko and when he tasted it, he didn't like what she gave him. Saiko is about to kill Bob for disrespecting her, but Luigi stopped her as he tells her that "Murder = Bad." A little later, together with Luigi, she races Mario to the hospital when he gets a heart attack after eating 500 hot dogs. Luigi was happy to see that Saiko did know how to be nice even though she claimed she didn't know what he was talking about and after delivering Mario to the hospital, Luigi thanks Saiko and hope that they could be friends, bringing Saiko a smile to her face and then drives away on her motorcycle.
She reappears as a main character/protagonist who was selling rocks since SMG4 accidentally bought a million of them. Her customer, SMG3, ended up buying 2 million, who was convinced he'd be much cooler than SMG4 by doing so, therefore Saiko Bichitaru became the highest seller in SMG4's Twitter Post Picture.
She reappears as a protagonist/main character in the restaurant of Bowser. She hates working without getting paid, as she sold two million rocks in SMG4: The Mario Hustle but received no money. Naturally, she got mad and refused to work without pay. Bowser begged her to keep working, and she inevitably joined the team to run the restaurant. She was assigned as a waitress with Luigi by Bowser. Saiko impatiently took orders from customers. When she served Shroomy his meal, she once again demonstrated her violent side by throwing the meal at his desk, but with surprising accuracy.
She and Luigi made a good team and they briefly celebrated with a high-five. A few scenes later, Bob came into the restaurant and ordered a meal, but when he urged Saiko to hurry up, she threw Bob out of the restaurant because of his annoying personality. Luigi warns Saiko, “Remember? Don't murder customers." After this, she tried to improve her attitude to the customers. Saiko received a lot of orders and gave them to the chef, Bowser, but he was unable to cook them all in time, which made the customers agitated.
While the customers are about to leave, Luigi called for everyone to an emergency meeting where Saiko admits that she would rather stay in the SMG4 Universe than go back to her boring dating simulator world. Luigi demanded everyone to work together and he utilized Saiko’s strength as he started throwing food at tables while Saiko threw customers to their tables. When their work was done, Saiko was seen hanging out with her friends in the end.
She comes back in the episode where she saves Mario from becoming a T-Pose Zombie. She is later turned into a T-Pose Zombie at the end of the video by Waluigi.
She appears in the challenges where both Mario and SMG4 must endure a date with her. She later assists the gang with their rap against Waluigi where although she had no lines in it, she does be their backup dancer.
She attempted to flee the Teletubbies with Tari but both were caught.
In this episode, she joined the gang in visiting Bob's Mansion. She later reconciled with Fishy Boopkins, agreeing with him that they're still friends.
She with Meggy and Tari took Boopkins to one of Bob's concert but the idea failed. She later told the girls to try to make him happy while she went to be Bob's fan.
Saiko became Bob’s manager where she helps him become a worldwide celebrity. Saiko gets inspired and decides to start her career as a band with the rest of the cast. After seeing what Bob's Diss Track did to Boopkins, Saiko teams with the gang to create a diss track on Bob. The diss track was so popular that all of Bob's fans started abandoning Bob by not listening to his raps, and throwing out all his merchandise. To make matters worse, Bob lost his new mansion without his fan’s support and Saiko’s management. The final nail in the coffin is when Bob tries to reconcile with his friends, to no avail.
She appears at the start still feeling pissed off with Bob regarding his diss track and betrayal of his friends. She later opens up her present (a body pillow/sandbag) but was disgusted by it.
She appears as one of Team Thicc's members. Her psychotic mentality assisted her in making the roasted chicken Team Thicc was working on as she claimed she worked faster if she was angry. Therefore, she told Shroomy to make her angry. Due to her craving for attention, she was unwilling to help her friends on Team Spicy to bake their cake to win Bowser’s cooking competition.
In this episode Saiko appears briefly as one of the characters that try to help Shroomy get a relationship with a red Teletubby, she tries to teach Shroomy to be tough, later Shroomy gets beheaded by a troll.
In this episode, she appears to complete a challenge that needs her to be nice. At first, she tries to help an old man cross the street but she was so creepy that the old man got paralyzed in fear and later got run over by a car. Then, Saiko tried to get a cat (voiced by Markiplier) from the top of a tree for a crying Koopa Troopa kid by using a chainsaw to cut down the tree and get the cat. However, she also accidentally crushes the kid. Not realizing it Saiko completes the challenge by stabbing a nearby vending machine that gives her milk which she gives to the cat.
In this episode, she appears alongside Tari and Meggy to rescue Fishy Boopkins, Mario, Luigi, and Bob from the officers Chris and Swagmaster69696969696. Attempting to get them off their trail, she tried to kill Swag numerous times but fail. In the end, Mario throws Fishy Boopkins to deflect the missiles from Swag's bazooka (Fun stick) (that shoots multiple missiles in one shot). This results in stopping both officers and ending the episode.
In this episode, she appears briefly as part of a challenge that needs characters, Bob, Fishy Boopkins and Mario to speak Japanese which Saiko judges. After beating up Mario and Bob for doing badly (especially Bob for insulting her), Fishy Boopkins speaks fluent Japanese (Using the Voice of Dio (from JoJo's Bizarre adventure)) and impresses Saiko, making him the winner of the challenge.
In this episode, the Anime Secret Service (A.S.S.) hunts down anime which forces Saiko to leave the Mushroom Kingdom (since she is also anime) and go to Japan, she takes Bob, Boopkins and SMG4 as her escorts while Mario stays in the kingdom to do a very dangerous mission for the anime cartel.
Continued from Mario's Illegal Operation, Saiko took the boys around a tour in Japan. Just then, she notices Axol after being mistaken for one of his creations by one of his fans. Realizing that he could bring anime to life (albeit for a while), she gets the rest to go after him. Eventually, they managed to catch up with him and after she showed him what happened back in the Mushroom kingdom, he agreed to aid them in unbanning anime.
Upon returning to the Mushroom Kingdom, the group was naturally denied entry by Swagmaster and Chris due to her. Using his paintbrush, Axol used some anime to distract them long enough for them to slip past the gates where SMG4 drove a stolen bus until they crashed into Meggy and the others in Shroomy's monster truck. Now reunited, the gang agreed to help Meggy get back her Splatfest equipment from Desti.
Saiko appeared in Meggy's house, along with Tari, and Meggy. She, Tari and Meggy are going on a "war" on Meggy's house. She then later gone insane after seeing the gun that she is holding and then gone shooting with her gun, continuously. Tari and Meggy told Saiko to stop, but to no avail.
Saiko joins SMG4 and Mario in defeating SMG3 for the sole purpose of beating someone up. She is confronted by Kizuna AI, who has a similar personality, and shoots her stating that there can be only one. After SMG3 is defeated, she and Mario tie him up and force him to watch 10 hours of UwU ASMR.
In the typical anime style, Saiko is an incredibly tall and skinny teenager with a curved figure and large bust, who towers above her love interest Fishy Boopkins. She has pink, curly hair with two different colored highlights at the tips: purple highlights on the right side, and yellow highlights on the left. Her eyes are purple and almond-shaped, with thick, curly lashes on the ends.
In terms of attire, Saiko is always seen wearing a tan jacket with a black tube top underneath, a dark-brown miniskirt, a black belt with a skull buckle, black leggings, and light-grey casual shoes. She wears a skull-and-crossbones pendant around her neck, and her hair is tied up in twin tails with two red bows.
In SMG4: Final Fantasy Mario, Saiko also wears a black beret, which is detailed with white trimming, a red gemstone embedded in gold, and white feathers on the side.
In the video SMG4: The Mario Hustle, Saiko wears an Atwood Sandy Palm Hat and a red short bow tie as her business outfit while holding her leather steel briefcase.
In the video SMG4: The Mario Café, in the middle of the video, she wears a tan bear hoodie hat as casual waitress appearance.
Just like her name, Saiko, which was derived from Psycho implies, she is a psychotic Yandere who causes death and destruction to everything she comes across, which is one of her ways to get attention. Since her debut, Saiko started as a nice and friendly girl who loves to hang out with Boopkins. When someone started to making fun of her and anything close to Boopkins, she will destroy anything to get her way, thus leading to Boopkins dumping her because of this reckless and violent behavior. Due to this, she becomes mentally unstable and is now even more egotistical so everybody can notice her.
In recent bloopers, Saiko changed to be repentant towards her past actions, which leads her to become a better person thanks to Luigi's advice in SMG4: Luigi's Lesson. Despite this, she still has moments of being a tsundere.
Despite her sarcastic and semi-aggressive attitude, she deeply cares for her friends. An example is in SMG4: Mario and the Diss Track where she used to be Bob's manager who helped him with his rap career, but when she finds out what Bob did Fishy Boopkins, she later helps the gang get by at Bob by making a diss track on a home. Another example is in SMG4: The Splatfest Incident as she appeared to be concerned about Meggy when she and the others see that Meggy was probably kidnapped. In the fight scene, she got mad at Desti when she accused her of being involved with what happened to Meggy when Desti saw how defensive she was of Axol.
SMG4: Doki Doki Mario Club
SMG4: Mario Battle Royale