Which Piece Am I Missing?

Trafalgar Law has been hiding a secret since he was 10 years old, ever since he ate the Ope Ope no Mi. The truth is that it didn't cure his Amber Lead Syndrome; it only withheld it, slowed it down. And now 14 years later it, his sickness rears its ugly head once more. Despite any and all efforts by his crew to save his life, it was not to be.

And Trafalgar D. Water Law........Died.

At least in that world.
After his "death" Law reawakens in the middle of a forest. And yes, while he remembers his past he has forgotten somethings. While he remembers what happened to his home and family, he cannot remember his home's name. While he remembers his adventures with his crew, he doesn't remember their names. Most everything else he remembers.

But there are somethings that he knows he shouldn't even know. That he died. That he's in another world. The basic things anyone in this "new" world knows. That in this world he's cured of his Amber Lead Syndrome. That he has been reverted back to the age of 13. And that he can't go back to his world. That doing so will disrupt the balance and throw the entirety of his world into chaos and destruction.

And so Law starts his new journey in search of something to do. And the first thing he comes across is a big egg with gray flame-like designs on it. Shortly after finding the egg, it hatches. And from it cames what is know to this world's society as a female exceed, a cat that can fly and talk. Law then takes it in and raises it, having a strange compulsion to name it Corazon or Cora for short.

Years pass and Law has grown to the age of 20, and made quite the name for himself in the country of Fiore. What do you think happens when Law stumbles upon an odd quartet in trouble, and provides the group with a little of support? Well they offer him a chance to join their guild of course!

(A/N- This is a crossover of One Piece and Fairy Tail, and maybe an Erza x Law. I don't know cause I ship Jerza)