spoilers ahead:
so basically, when the ML used his son's blood to bring his mom back he not only bought the ML but another swan which was the MC's ex. MC's ex was Lady Brabant's swan (later in the novel she was obsessed with an heir so she need him. But she was abuse him so much for a child. Anyway, there was a couple of misunderstandings between Roth and Anna. In the beginning if you remember ML burned MC's clothes which she sold for money he got his on it and burned so there was no way for Anna to go back either. So Ross was plotting against MC from the very beginning like she knew how to perform the ritual to bring the swan back but she didn't because she "loved" Roth and wanted Roth for herself. So to get the ritual successful Roth used his son to get right 'spell' because their demons they can brainwash and svan was the easiest for this task because ross was in charge of being teacher of svan. Fast forth to where Ross finds out that Anna but look at Brabant's red eyes, ross knew that Anna was the swan to get rid of her. Ross told correct way to get back to MC's ex. (I'm prob missing a few parts sorry). On the night of the red jmoon, MC's ex told Anna about the truth, however she was very conflicted like she truly loved Roth but the thought of being a replacement really bothered her. So that day she made a chocie of going home (there a bit more than that but I forgot) with her ex (even the ex offered Anna that he would share his clothe with Anna). So later that night, Anna went to meet her ex to go back to their world as the ex was looking for his clothes he couldn't find it (but his intention was not pure he wasn't gonna share Anna was just a conflict that get in his path to get back) but he got by Lady Brabant. (Ross was killed btw).As for Anna she met Svan her son and he was like don't leave and stuff and she was like I'll be back and he said lies. After Anna went to the place her ex told her she was waiting a while until she gave up and went back to the mansion. The house looked like dead but the ML's wife's room lit under the red moon she went in and met the ML who was really mad. gave her a the diary of his wife which led to her memories coming back. After discovering the truth of why ianna wanted to go back is because of her mom who was very sick. As well as, Anna was there for 5 years, she never knew why she was bought here but the ML and ML's father knew why. As well as, the ML's mother died by making her son the ML into a demon which the ML's father hated. As a way to get his revenge was to get ianna clothes when she was first bought here and killed the black magical so Roth would never be be able bring ianna back. So they were forced to marry, Roth was getting really soft towards ianna but her thoughts only about saving her mom. So the ML's father told her about a deal she would give birth to an heir he would let her go back. So ianna told Roth she wanted a child and Roth thought that she had forgotten about going home and would never but he was wrong. But frickin Anna didn't tell him the truth of what's written in the diary. Then basically the ML like fricked her and used magic so that she can never walk without ML's permission. And the worst part is that she accepted everything and lived her life cripple with ML only person moving the wheelchair. And the ML was portrayed as anger for the reset of the novel. (read the novel there is more) you can pick up from 37 novel ch based on where the manhwa stopped

does the ritual makes the mc stays on that world?