One Piece's Whole Cake Island arc has finally brought the climactic battle between Luffy and Kartakuri in the Mirror World to an end, but this was only one of the Straw Hats' big problems as Luffy still has to escape Brulee's territory.
Given as weak as he is right now this would be lead to even more trouble for Luffy, but the "mystery savior Mystoms" appears to help Luffy escape from the Mirror World.
Although Luffy was confirmed as the winner in the fight with Katakuri, he has exerted far too much power in the fight. Left with only a few minutes to rendevous with the other Straw Hats at Cacao Island, Luffy was struggling for a way out of the Mirror World. Luckily, "Mystoms" appears with Brulee completely tied up in rope and under his arm. He's given a hilarious title card for his name, and doesn't want to give away his true identity.
Luffy is all too happy to see Mystoms, and quickly "reveals" its Pekoms in disguise. Though it wasn't much of a disguise, Pekoms still wanted to keep his identity hidden. He's there to help Luffy get to Cacao Island because Pedro sacrificed his life for Luffy and the others. Pekoms isn't about to let Luffy die in there. Pekoms then throws Luffy over his shoulder and the two, with Brulee, prepare to leave the Mirror World
But even with this last minute help from a "surprising" ally, Luffy's troubles are only beginning. He and Pekoms will soon come face to face with Oven and a huge force of the Charlotte Family waiting outside of the only mirror remaining on Cacao Island. Sanji is off to the side waiting to spring into action, thankfully, but this is a dangerous situation for all of them. Pekoms is really putting his life on the line here to help Luffy as there's no good way for him to get out of this, even if the Straw Hats escape successfully.
Eiichiro Oda's One Piece first began serialization in Shueisha's Weekly Shonen Jump in 1997. It has since been collected into over 80 volumes, and has been a critical and commercial success worldwide with many of the volumes breaking printing records in Japan. The manga has even set a Guinness World Record for the most copies published for the same comic book by a single author, and is the best-selling manga series worldwide with over 430 million copies sold. The series still ranked number one in manga sales in 2018, which surprised fans of major new entries.