Ok here are my issues and fixes for you

- Your dragon will be only a a year old hatchling meaning its only hatched for a year it could have stayed in its egg for one other year

- Your dragon if uses any powers must recharge for three minutes (if a large blast of power must recharge for five) but can use his tail and claws still.

- Your dragon will not grow over 18 feet tall (if what you said about them demolising a city then NO he will never be able to get that much raw power remeber the idea of the story if to create peace not bring more chaos into it)

- Alsmo if your a new rider you can't train or raise a dragon very well why ? because peiple do not own dragons and half blood elves and dragons wouldn't cope very well unless they had around 15-20 years with each other to actually get a good bond going if they where on their own

- You said that the dragon can fuse with the person.........Erm maybe not the dragon is a dragon not a blast of cloud air or dust a dragon needs a pyschal form please

- BUT other then that love the new rider, Please do not be changing intoa  wolf forty times XD then people will want werewolves soon XD and thats going to be a pain