The loop starts:
He loses trust with everyone including Emilia, and they leave him in the capital.
He sinks into depression, but the only person who didn't leave his side is Rem, who displayed her unyielding love by continually caring for him.
He trains under Wilhelm, who is under Cruche's (one of the candidates) orders. He learns that the Roswall's mansion is in danger, and hurries out to get back to Emilia, breaking yet another promise.
But the road back to the mansion is hazardous due to appearance of the White Whale of Gluttony.
In his attempt to get back to the mansion he and Rem are captured by the Cult of the Witch, an evil cult who worship Satella the Witch of Envy, and schemes to bring the Witch back into the world.
Here's where the hell starts: 25 chapters of constant death, torture, and unspeakable horrors by the Witch Cult.
Subaru and Rem are tortured, mutilated, and killed by Betelgeuse, the Bishop of Sloth.
In one of the loops Subaru finds his way back to the mansion alone, only to find the whole village piled in a mountain of corpses, Ram mutilated in front of them, Emilia dead in the mansion, and an enraged Puck going out of control, freezing the entire region and instantly killing Subaru.
In another loop Subaru is driven insane from the torture he receives from Betelgeuse, who rips apart Rem in front of his eyes piece by piece.
This insanity lasts a whole loop as Rem tries to carry Subaru who has turned into a drooling madman and make back to the mansion. At the end of this loop, the two are again captured and tortured, but this manages to snap Subaru back to sanity thanks to his anger.