Avengers Dragon

Basically you're a dragon but you can shift into a human form as well. Your dragon form is similar to the one in the picture and your human form can be almost anything. You do have tattoos as a human, two massive tattooed wings on your back so that you can choose to fly and your tattoos basically become your actual wings. You can be any gender, appearance, race etc it's just you have to have the tattoos as a human. You're an incredibly powerful dragon, the last one in existence. Your race has a rivalry against the Titans (Thanos' race) and a long time ago they had a war. Because of both races being so powerful, the war just killed almost all of both races, no one won. Peace was declared but the war had destroyed supplies so much that eventually both races died out except for you and Thanos being the last survivors. The Avengers have heard of you and the power you have and so decided to seek you out for help against Thanos. You also know a lot about the Infinity Stones. You can choose whether to help the Avengers or whether to leave them fight by themselves. (Ignore voice btw) (also you live in a cave by a volcano in Antarctica. Mt Erebus specifically) (you know who the characters are)