Portgas D. Rogue felt herself slipping away after giving birth to twins. Yes, twins. She hadn't known she was having twins, but she knew Roger would have been overjoyed at having a son and a daughter. She even named them herself.
Gol D. Ace and Gol D. Lucy. They were hers, and whatever name they went by either Portgas or Gol, they would still be hers and Rogers.
Rogue knew she needed to keep them safe, and so she created a portal with the last of her strength, using the what little magic she had.
"Take care, my little light. I hope you have a great time in Earthland." Rogue kissed baby Lucy on her forehead, and sent her through the portal. She reached for baby Ace, but was too weak and the portal closed.
"Don't worry Ace, I'm sure you'll meet your sister again. I wish you well, little flame." And with those parting words, Portgas D. Rogue was gone.
Layla and Jude Heartfilia were walking along in the garden when they heard a baby crying. Curious, they searched the garden in search for the baby. They found the baby surrounded in light and roses. Layla walked ahead, unafraid. Jude followed behind her not too long afterwards. Layla picked up the child and cradled her closely, smiling at the fact she looked like her.
"Her name shall be Lucy, Lucy Heartfilia." Layla smiled. Jude smiled and they headed back to the mansion with their daughter, who would bring about change to both worlds.