You've been in TF 141 before being a good soldier till one day you got shot from one of Makarovs soldiers. Everyone thought you died but that wasnt the case.
You were brought in a lab and experimented on till once they were the only thing left was you being a Dragon hybrid. One with Dragon features but also the ability to Shapeshift into a dragon. They also took your memories from TF 141 so you wouldnt remember them once in mission.
Now its a mission where TF 141 is supposed to take down Makarov. They already managed to surround him so he couldnt get away. Makarov had a wide smile on his face which didnt ment good. They pointed the guns at him before suddenly the view got blocked by a dust cloud which suddenly came with something big landing on the ground. It was you. In youre dragon form now standing behind Makarov and you were big. Around 13 ft - 15 ft tall and you were on marakovs side...