From the story we could see that both of them had their own reasons.
Sylvia, because she wants to save the world.
Catherine felt betrayed because she didn't fulfill her promise which Sylvia also said that a promise must be fulfilled.
However it's a bittersweet ending since Catherine after her death achieved what she wanted to.
Dream Realm,
Dream Realms are different realms that don't interfere with the real world Endora.
They have their own landscape, sky, beings etc.
They are created by strong obsessive beings.
No matter if it's human, mutant, monsters or other beings.
As long as they have a terrifying obsession with something, the Dream Realm will be created.
In the game there are many Dream Realms because well Each Playable character has some kind of obsession.
They achieve a Happy ending with Sylvia's help but for Catherine, it was also a happy ending but only after dying.
After all she achieved what she wanted to after dying.
She could control the dream realm yet not control at the same time.
Dream Realms are also a kind of realm for a person which shows their hidden dark personality.
Damien shook his head as he looked at Sylvia with dissatisfaction written all over his face.
He is dissatisfied with her because Catherine is a beautiful woman, if it was a man or woman with an ordinary look, he wouldn't care much since he lacks empathy towards others.
But since she was a beautiful woman, and also a woman who will be in his harem so he is naturally dissatisfied with her.
He ignored all kinds of catastrophic or mass murder things she did because she is a beautiful woman ahem.
"What kind of look is this?" Sylvia was flabbergasted as she looked at his dissatisfied written face.
"Nothing, you... Forget it." Damien thought for a moment but finally didn't say anything.
'So since she is Catherine, how should I meet her? I mean I am actually capable of saving her village since I possess not only time elements but also space.'
He thought for a moment and decided to meet with her after obtaining a lot of dragon dissolving wings.
"Let's go, we can't wait anymore. Are you ready?" He asked everyone.
However they just rolled their eyes as he is the one who let them wait here.
Elsa comes to him as he has nothing on his body, she gives him a sword of ordinary quality.
She said "We must have some weapons to fight with the dragon right?"
Damien nodded, he chuckled as he took the sword while saying "Elsa, you are too kinda cute."
"C-cute?"
"Yes, cute and beautiful."
Hearing this, Elsa's face blushed while Celestia had dissatisfaction written all over her face.
One moment he was flirting with her and holding her hand but the next moment he started to flirt with her righteous sister.
'Hmph scumbag.'
She naturally remembers their promise to each other that all three sisters will have only one man.
She knows about it, but not Damien.
So he naturally fell into the scumbag category.
Damien saw dissatisfaction over Celestia's face, he walked near her, he put his hand over her shoulder as he said "Why is my baby angry? Who made you dissatisfied?"
"Hmph you ask while knowing."
Because she didn't refuse 'My Baby', Damien was quite surprised.
He looked at the favorability and was stunned to see 76 Favorability.
Of course he didn't know even though Celestia is dissatisfied with him but because it is her sister Elsa who he is flirting with, so because of her promise to each other her feelings naturally increased.
He was stunned and found no resistance from her body and looked at 76 Favorability.
He decided to get touchy-touchy with her.
He kissed on her cheeks as he asked "There, this should quell my baby anger right? Or do you want me to kiss you a few more times?"
His focus was on their favorability, he saw Sylvia favorability changed from 69 to 70.
Elsa's favorability changed from 53 to 67.
Celestia favorability which previously was 66 changed to 76 then now at 81.
He was stunned, no way he kissed Celestia, so why did Elsa and Sylvia favorability instead of decreasing rises?
'Wait... Catherine Name Added in Harem? With 100 / -100 favorability?'
He opened his status panel so he was stunned as he saw her name in the Harem section.
'No way? Is she attracted to my handsomeness? I mean... Sigh another girl who fell for my charm hahaha.' He thought quite narcissistically.
He didn't question the system as he felt his main priority was Celestia, but at this time he felt a murderous aura and scrutiny on his body increased.
He shook his head as he will find out about this later, he was for now puzzled about their increased favorability.
Of course he doesn't know about their promise so Elsa's favorability increased while because he didn't hide this from Sylvia so her favorability increased.
"Hmph, Damien you little lecherous. You say as if I wanted your kiss in the first place!"
Damien coughed while looking at her blushing embarrassing face.
Then he said "Let's go and hunt down the Sun Drake."
As he said his head jumped on the stronghold of Sun Drake.
As soon as he jumped, the Sun Drake monster, which was closing its eyes, instantly opened it and spit out fire from its nose as if getting ready to kill the invaders who dare to step into his Stronghold.
Elsa, Celestia and Sylvia looked at him.
Elsa and Celestia's eyes flashed because it seems not only his look but even his behaviour is kinda similar to their other sister.
This looks like reckless behaviour but he should have full confidence, as for why they can tell about it?
It's because their good sister also does the same thing when she is confident in something, quite reckless.
In fact what Damien didn't know is that the future direction of this world has already changed.
Because of their good sister, Elsa is not the game character Elsa who saves everyone and Celestia isn't the same Celestia who is quite bold to everyone.
***
Read My Other Novels!