In my story, the antagonist is possessed by a dragon. Well, I thought that maybe we should have more dragons (He is the last dragon originally), but well... you know. Dragons. They appear in literally any fantasy. So I was thinking: If I make them original, I could really build something interesting. But I'm out of ideas. This is basically a picture of Ra'anok (the afromentioned dragon): Ra'anok has scales of a jade black, much like those of a lizard. They cover his entire body apart from the belly. He has blood red eyes, and since he has lived among humans for so long he has nearly mastered the human tongue (most dragons can only speak the ancient language). Dragons can speak the ancient language (which people use to do magic), performing magic spells and such. They have two wings and can fly, and also have a tail. They are extremely hard to kill, and can be brought back to life easily by necromancers, for to truly kill them you must destroy their soul by piercing their heart.
A difficult question, but there is an answer. But there is no oiginal idea any more. For example, let's dissect my own novel. Does it have cliches? Yes. Is there anything much I can do about it? Well, yes and no. You see, on the one hand, if your story needs dragons, then there's nothing you can do in that sense. The cliche has to be there. BUT, there are some little things you can do. Be creative, for one. Twist things on their head. Play the 'what if' game for a few minutes. By doing that, you may well end up with dragons that aren't exactly the same as every other dragon out there. Secondly, make the rest of your story less cliche, if you can - again, ask questions about your world and characters. And thirdly, remember that you dragons will never be the same as anyone else's because you've written them into your story. Writing style matters tremendously. Just do what you can, and if your dragons have to be cliche to make your story work, then so be it. Hope that helps.
Stop worrying about making XXX original. Focus on writing well, and it won't matter what your subject is, or how many other authors have used it.
As has been said, Dragons are not original and pretty much wont be ever again as it has been done in every way possible. What you instead want to do is create a setting and a good solid story and try to find details that is special to you. If you are able to stop worrying about the Dragons not being original, you can start to form and make sure that the story and world you give them to interact with is. I mean just from your detail description I can picture a handful of different dragons from different forms of media, like the ancient language used for magic that drew my mind instantly back to Skyrim, for example.
Dragons can be original!!!!!! Think about it for a moment.....what about the Kimono Dragon or tiny lizards. I can call a t-rex that flies a dragon lol. A dragon is more of a sacred and special type of reptile that has significant powers that can be magical or physical. I would try to spice things up a bit and add small elements of what a typical dragon is and create your own spin on it. As Cognito also stated that do not work so much about the character so much. As long as you have a storyline and getting from A -> B and B -> C etc. you will be good.