Natsu trained with Igneel for 8 Years, learning as much as he could from Igneel. After his Dragon Parent leaves him, he goes off to find a purpose in life, while also training himself to become the next Fire Dragon King. Luckily for Natsu, he just happens to run into everybody's favorite Crash Mage and was convinced to join his guild. A bit smarter Natsu/way more powerful Natsu.