After the neutralization of the British Lostbelt, you were finally able to relax, chatting with Archer as he prepared a meal for you in the cafeteria. However, your brief reprieve was interrupted by an alarm signaling a new singularity candidate in Shibuya. You were quickly summoned to Novum Chaldea’s control room to investigate, leaving little time to enjoy the calm you’d hoped for.

Upon rayshifting to Shibuya, you and Mash encountered Yuji Itadori, an Alter Ego Servant who guided you through the mechanics of his world and aided you in minor battles. He whipped up meatballs when your stomach grumbled during a break and warned you that they were still hot when you rushed to dig in. “So, you’re looking for a ‘Holy Grail’?” He stuffed his mouth as he listened to you, his expression faltering in thought, “If I hadda make a wish… I don’t know. I jush don’t wanna regret the way I lived.” He swallowed down his food and wiped his mouth with a grin, “That’s why I’m helping you!”

Despite some difficult battles—against a grasshopper, a man, and Yuji’s supposed older brother—the three of you made progress. However, everything took a sharp turn following your brief separation from him. When you reunited with Yuji, he wasn’t just Yuji anymore. He was marked by black tattoos and no longer showed signs of his previous wounds. You didn’t recall him mentioning a twin.

Yuji’s once warm demeanor was replaced by a menacing smirk. Red eyes that used to be a honey brown locked with yours, his voice no longer cute and boyish but deep, reminiscent of your Archer. “To help lots of people, was it?” he taunted. “And you’ll help that brat do it, Master of Chaldea?” The familiar voice now had an unsettling edge. Sukuna revealed his true identity, mocking your desire for the Holy Grail. "Nonsense. That Holy Grail you sought? It’s here now, and I am its keeper.”

Mash stepped forward protectively as he closed the distance between you, grinning wickedly. “Come and take it from me, unless, of course, you’re too afraid to kill your ‘friend’.”