Subaru smiled as his role was completed. Emilia killed him and became the King of Lugnica. He achieved his goal and accepted death after dying countless times. He was ready for his story to end. He thought about why he went so far to help someone he barely knew as his vision went black, and he opened his eyes to see a garden. Memories began to flood his mind of every path he took as he breathed, and the air surrounding the garden he was in calmed his mind. He sees now, whom he knows as Satella sitting on a bench, shedding tears as he walks up to her with so many questions to ask.
Satella mumbled as tears fell on her face, "Subaru, why? Why do that…."
"What the hell am I? How many times have I done this? I don't even know how my brain can process so many memories. How many times did I live?" Subaru asks as the memories that flood his mind begin to form him into a more stable version of himself.
"I… have to restart you."
Subaru eyes widen, "Satella, what is this? If I have been restarted this many times, all your doing is torturing my soul… this is hell. You said you loved me in so many of these lives, but what your doing is torment. Tell me why?"
Satella looks down, "You still never kill me. His plan failed, and he died, and I've been waiting for so long to die. I do love you, Subaru. You always cared for me, and even if that's not me, then that's enough for me to love you."
"His plan? How long have you been trying to do this? How long have I been in this world… what the hell? Memories are being erased and restarted over and over." Subaru questions, "Why do I love you so much now? Am I Flugel?"
Satella wept, "No… your not. I'm going to reset you. I can't talk about th-"
Subaru grabbed her hands, "NO, PLEASE NO. Why do I love you? I don't understand any of this… don't I get to know? Don't I get to know my 'purpose' in this world I thought would be a new start for me?"
Satella froze, "...why do you love me? I'm so cruel to you. I just want to die, but you never take the path of killing me."
Subaru stared into her eyes as he realized, "Your… Emilia?"
Satella shed tears as she tried to respond, "She-s th-e othe-r hal-f of my so-ul."
"I hate this. Satella, I'm done if that's true, then I've been letting you suffer for a time I can't comprehend. Is that all you want is to die?"
"I… can-t sto-p it envy wi-ll res-et you."
Subaru sat on the wooden bench beside Satella, placing her head on his chest, "You watched me live that life I just did… what the hell would that even feel like? I can't do this anymore, even if you erase my memories. You said yourself I never reach the point of killing you."
Satella wiped the tears off her face as she enjoyed the comfort she rarely receives, "He planned to have… someone in the future who could hold all seven I can-t…."
"Tell me, please. I want to die too. If I'm bound to repeat the same existence repeatedly, that's worse than hell. You're suffering more, you remember… you just saw a version of me that went insane… let me help you I don't care if you think I can't I will."
"You have to kill me. At first, he planned to have my soul and Emilia's be connected and Envy removed… but someone altered Emilia's soul before you even arrived."
"I don't want to kill you. I can't. If I did kill you, would you die with a smile?"
Satella trembled at the question, "I…."
"Then you don't want to die. You don't deserve to die, either. This is so cruel. Even if I was restarted countless times, you had to watch. You are not even in control of your mind. How are you now?"
"You obtained all seven witch factors but… you would've had no way to kill me at the point you were at. That's why you can see me. I don't want this to fade, but…."
"SATELLA, I DON'T EITHER. What is a soul? When someone's name and memories are eaten, they go into a coma state. Without memories, you don't have a soul. You are just a blank slate. Satella, I love you. You are the only one that knows me. I forgive you for anything you think you did to me… were both tortured people that just wanted to escape their life and ended up choosing death as the best option. I want to live a life with you, not in this garden but live a real life with you."
"How can you say that? I've done so much wrong to you that I couldn't save you so many times. I hate it. I hate I can't do anything but watch…."
"I love you because of what you are. If I loved your soul every time I went into this world, then what's the difference? I can't stand this. Does god hate us? For me to continue to restart endlessly for a goal, you don't even want yourself. You don't want to die, or you'd die with a smile you want to live again. Why do you love me?"
"I didn't know at first… not until I saw you try so many times and say you'd save me those words. I want so much I want you to save me. But the only way you can is to kill me…."
"I can't kill you, and I won't. I can save you if I hold all seven witch factors right now."
"How? Every time you say those words, my heart pulses with hope."
"It is even worse that I let you down so many times. Giving you hope and then failing you is beyond cruel. Memories are what make a soul a person. If I can eat your memories, then return to the start and return them to you when I meet you… wouldn't that be the same as the soul-merging thing?"
"Subaru… you'd be with me. You'd remember all the terrible things you did, and I would too."
"So I can save you. Let me do this so we can restart together. We can talk about our mistakes, but I can be with you. If someone is altering Emilia's soul, how am I supposed to save you? With memories, I can… I don't want to forget again. You'd be freed from envy as your memories would transfer to your soul without envy."
"Subaru it would work but are you sure you want to do this? If memories are souls, why do you love me if Emilia has different memories?"
"If her soul was altered and I already know her memories have been… I just want to live a true life. No more false memories or lies. Just a single life with you where we can finally enjoy living. No more return by death. No more suffering for you and repetition for me." Subaru leaned towards Satella, "I want to live a true life. I can't do that without you. I can't save you either unless you let me do this. I want to see you smile and laugh. You deserve it, and I want to see myself live a true life. Would you die with a smile if we do this?"
"I… would. There's so much I want to tell you, so many things that happened before I got the envy witch factor. I never had someone to talk to. Subaru what about Roswaal and you not being able to return by death? How will you survive?"
"There was a sword saint you knew, right?"
Satella trembled, "Yes, why?"
"Was everyone insane in your past? But I do know someone that can keep us safe. I already have a plan we can do this. I want to learn how or who altered Emilia's memories and soul. I feel like all my lives in this world were tainted by that." Subaru held Satella tighter, "I'm glad you didn't reset me before we could talk. We probably are the two that have suffered the most in this world, and now it's time to enjoy life. It's only fair nobody should have to endure this long and sit alone in despair. Satella, when I leave, teleport me to your seal. I'll eat your name, find a way to restore it when I meet Emilia, and then reset me."
Satella confirmed while embracing Subaru's comfort, "Are you sure there isn't going back if we do this? If you die, then… it's over."
"Yes, I'm sure." Subaru pecked Satella's lips, "This is a real new start, and you'll be able to be with me. No more suffering, no more lies. It's the life I would've wanted in this world, and we both suffered enough to get to this point. Let's do it."
Ok, so to make things clear:
Emilia = Satella. They are the same soul (Satella is the pure one, not WoE or Satella with the envy authority)
Subaru is not Flugel (I think this feels better to do as it gives more justification for why Subaru loves Satella and vice versa, and having a new start feels better this way)
Finally, I think memories are an exciting idea to explore as we know, Gluttony, when someone's memories are eaten, they go into a coma state. So in my eyes, a soul is nothing without memories and identity.
When Subaru entered the garden he got all the memories of all his restarts which is why he suddenly changed from his Pride IF Subaru.
When they return no RBD, and I wonder how Puck will react to this sudden reunion