Pirates at Fairy Tail
Both Team Natsu of Fairy Tail and the Straw Hat Pirates eventually learn of Thirros' evil intentions, which was to use his magic crystal ball to enact a magic ritual that would spread a blanket of darkness over Magnolia and Fairy Tail, and in doing so, sap away all magic from the Wizards, leaving them powerless forever, but they managed to defeat him in time and stopping the dark magic ritual. They then learned upon his defeat that his Shadow Magic was a sort of double-edged sword; defeat in combat meant that the Shadow he entered a partnership with gets to take his soul. Thirros' Shadow emerged on its own large and frightening to everyone. The creature then grabbed Thirros and dragged him into its shadow where he disappeared with nothing but a screaming echoing into the air before the Shadow disappeared as well They returned as heroes to Magnolia.
The Straw Hats and Fairy Tail went on several more adventures together, facing down powerful enemies, encountering new friends, and eventually discovering a powerful magic spell that would summon them back to the Grand Line. The pirates bid farewell to their friends with tearful goodbyes, but as they left upon their ship, they all bore the mark of Fairy Tail, signifying them forever as friends of Fairy Tail. Every wizard of Fairy Tail and their neighboring friends attended to see the Straw Hats off at Hargeon. Magnolia herself, after the Straw Hats defeated Thirros, now flies the Straw Hats skull and crossbones over their city as a reminder to their brave deeds.
The grand wizard performed the magic spell offshore, and a mighty typhoon was summoned, snatching the Thousand Sunny up and making her disappear into the sun. When the typhoon dispersed and laid the Thousand Sunny gently back into the sea, Nami found their normal compass going awry and their Grand Line compass function normally again. "Alright crew," Luffy called to them all atop the prow. "Set our course for the next island! Raise the sails, take the helm, and let us head forth for the Romantic Dawn!" Everyone cheered as their trusty vessel guided them towards the rising sun. They took a short break from their original adventure for a brave new adventure in a brand new world full of magic, wizards, and strange creatures, but of all the things they encountered in that world, the one thing that was most important to them was the friendships they made with the people; they now wear their emblem forever upon their skin, and back home, Fairy Tail simply has to look inside on the banisters and outside on the top of the guild to see the Straw Hat's jolly roger themselves. They will be friends now and forever, even when they are all worlds apart.
THE END
A/N: I'm sorry to say this, but Pirates at Fairy Tail is being discontinued and ending on this note. I apologize to anyone who is disappointed, but I personally have lost interest in this story and I have no ideas left for it. Besides, I have grown more attached to my other stories which I work on more often than this one, which was on hiatus for over a year as well. Again, I'm sorry, but thank you all for the support and I'm glad everyone liked Pirates at Fairy Tail so much, especially for my first crossover.