"Why do you love me so?" Zeref rasped, flabbergasted. The Black Mage of Death gazed questioningly into her eyes, struggling not to get lost in them. "I am shrouded in darkness, you are filled with light. I am Death incarnate, you… You are Life itself."
"Light cannot exist without darkness, just as I cannot exist without you." Mavis grinned gently, tilting her head slightly to the side. She took his hand in hers, eyes smiling like rays of sunshine. "Death only gives way to Life. You leave more room for me in this world; I give what you take away. The result is equilibrium."
"So naive…" Zeref sighed. "Are you not afraid of my curse? I killed you once, and it is not impossible for me to kill you again." He pulled his hand away from her lingering grasp.
"You did not kill me. You released me from my own curse, the one we shared. You did me a favor. You of all people should know that the worst curse of all… is immortality." She replied. "Therefore, I am not afraid of death."
"Well, I am. I am afraid of Death. I am afraid of your death. I am afraid for you." Zeref retorted. "Just by loving you, I put you in great danger. It happened once, and it can- no, it will happen again."
"Zeref-" Mavis began.
"If you truly love me, you shall let me go, for you own good, because I will kill you without hesitation. As long as you are with me, you will never be safe. I cannot control my own power. You of all people should know the effects of this curse." Zeref growled. "Everyone I love dies. Everyone I get close to perishes. Everything around me expires. Death surrounds me. It is inescapable."
"I escaped my curse, not through death, but because I learned the importance of life." Mavis said gently, stroking his cheek with a dainty hand.
"But… How?" He asked, bewildered. He grasped her hand with his own, holding it against the side of his face.
"Because of loving you." She said with a light chuckle. "I can do the same for you. I can make you remember the meaning of life. I can help restore your faith in humanity."
"That's not possible, I'm afraid I'm already too far gone. I'm a monster. You can't save me. I cannot be redeemed." Zeref said despondently.
"Your past does not define you, Zeref. It is what you do with today that counts the most. As long as you work towards a better tomorrow, your soul is saved." Mavis said, moving closer. "And if it isn't, then I will burn with you for all eternity."
And with that, she went up onto the very tips of her toes, and kissed him, sealing her promise for the rest of time.
"You belong with the fairies, not with me…" He murmered.
"You're more of a fairy than you think you are," She murmered back.