The Knight who was a Dragon Shifter

Here in the Paradis Island in the walled cities, They were invaded by monsters such as the giants, gargoyles, demons, black knights, and ogres. The one leading was the Destructor. He despised humans and was given the nickname "the demise of humanity." Two years ago, him and the Legion of Darkness attacked and destroyed Wall maria, but he wanted to kill everyone else and destroy the other walls as well. Unfortunately, one boy named Eren Jaeger swore to defeat the Destructor by becoming a knight of the scouts. But what he doesn't realize is that he has more power in him than he thinks.