Once upon a time, in the peaceful Mushroom Kingdom, Mario, the hero known for his bravery and determination, had just defeated Bowser for what seemed like the final time. The Mushroom troops cheered for their hero, celebrating the victory and the return of peace to their land. But Mario, always restless and seeking new adventures, couldn't settle for the comfort of the kingdom just yet.
His adventurous spirit led him to a destroyed warzone, where the Mushroom troops continued their fight against the formidable Koopa Troops. Mario, feeling a sense of guilt and responsibility, decided to observe the battles and reflect on the times he had faced Bowser. He found solace in the chaotic aftermath of the war, contemplating the sacrifices made by the troops and the resilience of the Mushroom Kingdom.
Exhausted from his reflections, Mario eventually laid down to rest, hoping to find peace in sleep. Little did he know, his slumber would take an unexpected turn. As he opened his eyes, he found himself in a dark and unfamiliar sewer. The surroundings were dimly lit and felt different from any sewer he had encountered before. Intrigued by the unknown, Mario cautiously ventured deeper into the sewers.
To his surprise, Mario stumbled upon a trapdoor that led him into a mysterious cave. As he explored the depths of the cave, he stumbled upon an ancient book titled the Necronomicon. Unable to comprehend the cryptic words inscribed within the book, Mario decided to keep it, sensing its significance.
As Mario continued his exploration, he unknowingly stumbled into a portal that transported him outside a mysterious castle. Eager to discover what lay within its walls, Mario attempted to enter the castle, only to be stopped by a formidable gargoyle. True to his nature, Mario easily defeated the gargoyle and stepped into the castle.
Inside, Mario encountered May, a peculiar individual who seemed to hold a personal vendetta against him. May referred to him as "Red Stache" and claimed that Mario had sealed her father, Derris, the Demon King. An unsettling realization dawned upon Mario as he learned about Derris' daughter. Fear and uncertainty gradually caused him to step back.
Suddenly, May transformed into a perfect clone of Mario, except for her white overalls. A clash between Mario and May ensued, each trying to overpower the other. Despite May's efforts, Mario eventually gained the upper hand and brought her down. May, refusing to admit defeat, reverted back to her base form, determined to continue the fight.
In a desperate act, May entered Mario's body, attempting to take control of his mind. Mario found himself involuntarily teleporting through various locations, caught in a struggle against May's influence. His journey through the chaotic realm continued until he stumbled upon a dark and demonic sword known as Zanmato. Sensing its power, Mario picked it up, unaware of the consequences it would bring.
Time passed, and Luigi, Mario's faithful brother, ventured forth on a mission to find his missing sibling. Riding on a minecart, Luigi headed towards the ominous forest, hoping to reunite with Mario. To his surprise, Luigi found Mario, albeit different from his usual self. Mario warned Luigi that this world they were trapped in was but an illusion and that they needed to escape. Mario's teleportation abilities sent him elsewhere once more, leaving Luigi bewildered but determined to save his brother.
Before long, Luigi encountered May in a dark tunnel by a mysterious teleportation circle. An intense battle ensued, but May transformed into Mario, cunningly deceiving Luigi. However, the real Mario arrived just in time to reveal May's true identity. Before the brothers could react, May transported them to a dimensional rift, where Derris was sealed.
Seizing the moment, May stole the Necronomicon, the final piece to free Derris. With all the necessary artifacts assembled—the Shadow Scythe, Toadstool's Crown, and the Necronomicon—Derris awoke from his eternal slumber. Luigi engaged in a fierce struggle against Derris while Mario continued his fight against May. Iris Mandragoran, the Lord of Time Streams, appeared, freezing time to address the dire situation.
Realizing that May killing Mario was not meant to occur, Iris spoke to Mario, urging him to defeat Derris and May at any cost. She granted him a portion of her power, The Power Iris gave Mario grew as she tapped into his hidden power, entering Blank Mode with his eyes turning completely white. allowing him to unfreeze time and rescue Luigi. Mario's newfound strength dispelled May's control over him. With a powerful punch, Mario sent Derris flying backward. Mario resolves to seal Derris once more, May attempts to stop him but her soul was temporarily punch out. transporting Derris back to the year 1000 AD, the period when he was originally sealed.
In a final desperate attempt, May tried to seize Luigi, vowing to have his brother if she couldn't have her father. Mario, with Blank Mode deactivated, sprinted towards May to save Luigi. However, Luigi, understanding the gravity of the situation, convinced Mario that sacrificing himself was for the greater good. Tearfully, bidding his final farewell, Luigi and May are transported away, leaving a devastated Mario behind. He collapses and falls into a deep sleep, hoping to forget the painful ordeal.
However, the enigmatic and powerful being known as Iris Mandragoran, the Lord of Time Streams, intervenes again, revealing a way for Mario to save Luigi. In order to do so, Mario must be sent back to August 26, 599 AD, the day he initially sealed Derris away. Unknown to Mario, during his past adventures involving time travel, he had unintentionally fallen into the year 599 AD, leading to a divergence in the timeline. Mario had prevented Crossdio, the sealer, from completing his original plan, which resulted in the war initiated by Crossdio.
With the hope of rescuing his beloved brother Luigi, Mario accepts Iris's proposition and prepares to embark on yet another extraordinary journey—one that would take him back... to the Chaos...