There is a reason why Den has an automail leg. You see, he leads sort of a double life. We all known him as Den the dog, but to others, well, he isn’t a dog.

To others, Den is a wolf. A wild one.

Den was in the forest one day, when he came across his archenemy’s wolf pack, and his archenemy. It was an all-out brawl of the wolves.

He fought bravely, and finally, it was a one-on-one fight with him and his enemy, Okam. They circled, fangs bared, claws clashing.

Finally, Den defeated Okam, but his leg had been damaged. They couldn’t save his leg, and it was replaced with automail.

Den still escapes once and awhile to protect the forest from Okam and his wolf cronies. And that is the reason why he has an automail leg.

The end.