"W-who are you?"
The other Sona smirked and replied, "You're asking me that? I'm you and you're me. Well, to be more specific, I'm the more honest you."
Although she got her answer, Sona could hardly process anything with the fear crippling her thinking mind. She didn't even notice that her eyes were darting around and her body was convulsing. If this is the real world, she would have already made a mess of herself.
Seeing this, 'Sona's' smile mellowed out as she instantly reappeared behind Sona, "Look at how pitiful you are now. He wouldn't like it if he were to see you like this, would he?"
Sona didn't even question why the other her had disappeared in front of her and instead asked, "H-he?"
"Who else but the love of our life, Kisuke?" 'Sona' whispered into Sona's right ear. Embedded within it seemed to be a power that crippled the latter's almost broken mind and she didn't even notice it.
"K-Kisuke? W-where is he?"
'Sona' wrapped her arms around the shaking Sona and whispered once again, "That's not really important right now. What's important is that you accept that I'm you, and you're me. To prove that I intend you no harm, let me remove this fear that has been bothering you~."
And as she finished her words, the fear that Sona was feeling really disappeared along with its effects. Nevertheless, Sona was already too light headed to even understand what was going on and 'Sona' couldn't help but smile further at this development, "See? I meant you no harm. I'm only here to help you~."
'Sona' then proceeded to point towards a certain direction and Sona unconsciously followed her finger to see a small hole within the darkness, depicting what's happening outside, "I'm here to help you realize your true potential and let out all the misgivings you've been keeping to yourself."
Sona stared blankly on the tunneled hole and saw two familiar figures standing close together and reached out to them with one of her arms. She wanted to call out to them but before she could do so, 'Sona's' hand grabbed her outstretched arm, "What you need is my help, not theirs. In fact, they are part of your problems."
"...Problems...?"
"Yes, they are.", 'Sona's' smile grew deeper, "You've always wanted to be a normal girl, maybe, a normal human girl living in a normal society. Since you know that can't happen, you wanted a part of it at least. That's your desire."
"...Desire..."
"Yes... Desire... And the two of them are in the way of it." With her words that had a strange compelling power behind them, 'Sona' poisonous words entered Sona's subconscious mind, "Nee-sama is competent... Way too competent. That ability of hers that brought her the position of the Devil King only made things worse for you."
"So that you wouldn't tarnish your family's name, you had to strive for better, completely disregarding all those sweet things that the other youths of your age experienced. Even then, it still wasn't enough as you needed to have a fiancé to completely solidify your family's power. Although you were able to find a way out of it, you had to triple your efforts just to prove you didn't need someone like that."
"Nee-sama, on the other hand, had all the freedom that you ever wanted and questioned why you didn't have it. It's alright to be jealous. It's alright to hate. It's your privilege for working so hard yet getting almost nothing in return. You could have had a better life without her."
Those are very far-fetched and nonsensical words and if it was the usual Sona, she would have brushed it off as nothing but ridiculous ideas. The current her was very far from normal and it became words of 'truth' for her, giving birth to jealousy and hate that she'd already deemed absurd long ago and would only have felt by her immature self.
To make it worse, the black space amplified these negative emotions just like what it did to her irrational fear that broke her earlier.
Of course, 'Sona' still wasn't done as she continued to the next person, "And the love of our life, Kisuke. You fell for him, but he couldn't give you the ideal romance that you wanted. Instead, you were stuck sharing him with many others that you couldn't help but feel inferior to."
"You knew well enough that you fell for the wrong person, but what could you do? You can't control your feelings and it also felt like he wasn't reciprocating your feelings enough. Not to mention, you also knew that it wouldn't be long before our Nee-sama fell for him too. By then, you might not even have a place beside him anymore."
Uncontrollable jealousy and hatred burned brighter as noxious words fed her fragmented consciousness, "...What should I do?"
Finally, the smile on 'Sona's' face devolved into a crazed one and she replied, "That's easy~! Prove to your sister that you have the ability to be better than her and take Kisuke for yourself."
Even if 'Sona' wanted Sona to wreak havoc as much as she wanted, she didn't want to break the 'spell' by giving her ideas that were too extreme.
"...I don't have power."
'Sona' pointed to the hole once again and said, "You don't have power? Take a good look again. You're destroying them. Even Kisuke's regenerative powers can't keep up. You can definitely do it."
"...I'm doing this?"
"Yes. Just follow my lead and you'll get what you've desired all this time."
At this point, Sona was slowly sinking into the darkness as she let herself be consumed by her jealousy and hatred.
'Sona' let go of Sona, satisfied with the outcome, "That's it. Stop holding back. Everything will be fine."
With only Sona's head remaining outside of the pool of darkness, 'Sona' finished her words, "After defeating Nee-sama, you can then neutralize Kisuke and run away to somewhere. If even that's not enough, you can take out the rest of the girls so that he wouldn't have to think about anyone else but you."
And that's when 'Sona' became complacent and made a mistake.
The hate within Sona's eyes worsened, but they also became clearer. 'Sona' thought that everything went as she expected but all of a sudden, Sona's arm came bursting out of the darkness, grabbing Sona's neck, "!? Guuhh!"
'Sona' tried to dodge, but it was already too late as Sona carried her up as she got out of the darkness, "How dare you!"