Returning from his death, Subaru realized that he had returned to the point where he had his meeting with the Petelgeuse attack group, quickly getting his mind straight when the others began worrying about him. Going through the meeting once more, he explained the basics behind Petelgeuse's Authority based on experience, then headed off with the group to Roswaal's land. The group arrived as planned, with Wilhelm visiting the mansion to alert Emilia, and had her evacuate in a Dragon Carriage with the village children. A short while later, Subaru confronted the diguised Witch Cult members in the group of merchants he hired, preventing them from contacting the others through a Conversing Mirror Meteor. Two of the three members tried to fight back, however all three of them were incapacitated by Wilhelm, Julius, and Ferris, allowing Subaru to interrogate them. He began interrogating them after Ferris "encouraged" them a little with his Water Magic, nonetheless he was unable to get any worthwhile information out of them, as they apparently didn't know anything more than what they were told.
Turning his attention away from them, he tried fiddling with the Meteor, accidentally undoing the magic on them, helping Julius determine where the Meteor was connected to, which he deduced were two places; one was a place in the forest to the west and the other was at a place a short while away. Seeing that the Meteor had been compromised, the incapacitated Witch Cult members tried to attack them, forcing Wilhelm to kill Ketty and Ferris to incapacitate the other two even further. Sensing an opportunity, Subaru asked Ferris to use his Water Magic to control one of the members to give false information to the others, subsequently having the Fang of Iron members to go off and clear them out. When the Fang of Iron members returned to report on the results, he was shocked to see that Otto was with them, who they found captured by the Witch Cult. Otto explained that he had tried to reach the village first to make sure he got a part of deal, though unfortunately he had been captured by the Witch Cult on the way there, and finishing his tale, was horrified to learn that he had missed out on the opportunity. To add on to his misery, he was ordered to stay in the village, as they couldn't risk letting him escape if he was a spy.
Once their preparations were complete, Subaru visited Petelgeuse in front of his cave, pretending to be a supporter of their ideals in order to infiltrate them. He was a little worried asking about the trial, as the last time he did so Petelgeuse asked him to present his gospel book, nevertheless this time around the madman obliged, revealing to him that he was commencing with the trial in order to determine if Emilia was a worthy vessel for Satella. Subaru expressed his disgust at the thought but made sure to keep his Witch Cult persona in front of Petelgeuse, yet he asked him to present his gospel book, which he avoid by successfully talking him into accepting him regardless. Leaving the gospel matter aside for the time being, Petelgeuse asked him if he had taken in Witch Genes, thinking he was pride, but at that moment the Conversing Mirror Meteor in his pocket activated, causing him to turn his attention away from Subaru. Taking advantage of his confusion as to why someone other than his subordinates had the other Meteor, Subaru landed a hate filled punch straight to his face, sending him flying off to the side. Petelgeuse was confused at first, though he quickly regained his composure, attempting to kill Subaru with his Unseen Hands, and was shocked to see that he could see them. Realizing that almost all of his fingers had all been killed, he began thinking about what could've happened, coming to the conclusion that he could just use the remaining finger and their group in the cave to overwhelm him with numbers, nonetheless his hopes were dashed when Mimi and Tivey collapsed the cave with their attack.
Not understanding the situation, Petelgeuse referred to his gospel, coming to the conclusion that Subaru was pride based on his actions, however he rejected his answer, stating that he was Natsuki Subaru, the Half Elf Emilia's knight, prompting Petelgeuse to declare that he was going to kill him. The three immediately started running as the madman began throwing things at them with his Unseen Hands while being carried by several others, and soon after both Mimi and Tivey were hit by the black wave caused by his Authority, forcing Subaru to carry them to Patrasche. Riding on Patrasche, the three of them ended up at the collapsed cave entrance, where they were joined by Julius. Leaving the two incapacitated siblings on Patrasche, Subaru agreed to fight with Julius against Petelgeuse, who appeared at that moment from the forest, intent on crushing them with a massive amount of Unseen Hands. To his surprise, Julius cut them all down with a sword strike imbued with the power of his Spirits, with Subaru explaining that Julius was seeing what he was seeing through
Nect. Julius continued to fight against the Unseen Hands with his imbued sword while relying on Subaru's vision, causing Petelgeuse to attempt to get rid of him first, forcing him to fall back and protect him, subsequently returning to his fight.
Eventually, Julius managed to get rid of all of the currently deployed Unseen Hands at once, creating an opening for him to aim an attack straight at Petelgeuse, who used Ur Dona to create earth walls to try to protect himself. Subaru destroyed the wall in front of Julius with a fire magic stone, allowing Julius to impale Petelgeuse against another earth wall with his imbued sword, nevertheless the man himself wasn't that concerned about losing his body as he could take over Subaru's body. Just as he undid Nect, the madman took over Subaru's body, which he claimed was a good vessel for him. He tried to attack Julius, however Ferris incapacitated Subaru's body with his Water Magic, preventing him from using his Authority while Julius had Patrasche escape with the siblings. Petelgeuse refused to accept his defeat, stating that he was dedicating everything to Satella, prompting Subaru to let him meet the witch herself by mentioning his Returns by Death. Immediately, their consciousness was pulled into the shadowy area where Satella was waiting. Petelgeuse was excited that he was meeting with the witch, nonetheless she wasn't happy at all, stating that he wasn't "that person", and started to become angry, forcing him out of Subaru's body. As he disappeared, she began expressing her love for Subaru over and over again. Returning to his original body, Petelgeuse couldn't understand why the witch rejected him, and began retreating to the rock face to escape from Julius. Not having any energy left, he let out one last Unseen Hand that eventually destroyed the rock face above him, causing the rocks to fall down onto him and crush him to death. Confirming that he was dead, Subaru told Petelgeuse that he had been slothful.