As the night flew by, the party was slowly dying down. Natsu, after his brief scuffle with Gray, noticed Lucy, slumped over the bar. She seemed to be asleep. He grinned and walked over, placed a kiss on her shoulder. She stirred awake.
"Wakey wakey Sleeping Beauty" he teased
"Well well well, isn't it my dragon" she giggled back. All of sudden, she yawned, the day's events really took it's toll on her. Natsu grabbed her hand and walked her back to their hotel. He took the opportunity to talk about their relationship.
"Luce, you have no idea how happy you have made me today, but there is something I need to tell you." Lucy stilled and looked at him in the eyes. He took the opportunity to caress her cheek with his calloused fingers.
"Dragons slayers, much like dragons, are monogamous creatures. When we find our mate, there is no one else out there. I knew you were my mate since the moment I laid eyes on you all those years ago. I am such an idiot for waiting around to tell you. When I saw the Future Lucy die..." He voice began to crack. Lucy took the opportunity to silence him with a chaste kiss and wrap her arms around his waist and pull him into a much-needed hug. Natsu reciprocated whole-heartedly.
"Natsu, you don't need to say more, I already know about dragon slayers and mating and what that means for us. Natsu, for the longest time, I kept thinking about that day we met in Haregon. Bora used a charm spell that worked on all the women there, including me. Then you showed up and I snapped out of it. I couldn't figure out why. When I found the library here in Crocus, I looked up charm spells with Levy. Natsu... s-soul-soul mates are immune to spells that toy with love. Natsu we're..." Now it was his turn to shut her up.
"Enough talking Luce, there is one thing I need to ask you. Lucy, I need you to think real hard about this because it will be forever. Lucy, will you be my mate?" Natsu was holding his breath.
"Natsu, I can't think of anyone else I can spend the rest of my life with. Yes, I will be your mate Natsu, yes!" She happy exclaimed.
Natsu was elated and spun her around. He was in heaven right now. He happy took her back to her hotel room. They spent the entire night expressing their love for one another; completing the mating ritual. Their lives were officially bound to one another for all of eternity now. Lucy had a mark on her neck. She and Natsu also had a mental link between the two; this link allowed them to sense the other and their emotions. The eventually fell asleep in each other arms, backing in their bliss.
Meanwhile, across town, an enraged Lisanna was looking around for a dark magic shop. She refused to accept Natsu and Lucy's relationship; it should have been her. She had to do something to break them up. She finally stumbled across a shop that what she was looking for; a potion that would allow her to control people. Little did she know that such potion and spells don't work on dragon slayers.