Blaziken. With hard work, determination, and inability to find Sootopolis City until 300 hours in.
Lol this was how it was for me in Sapphire. I had no idea what I was supposed to do (I had to go back to that beach town and go to the museum or whatever it was.) and did nothing but train my pokemon in Mauville city until my Blaziken was lv. 72 or so before I lost the game and my GBA SP. :(
I believe my first was my starter Charizard in Leaf Green.