Damian has spent several years serving aboard various stations an colonies as a Quartermaster, he was experimented on in genetics over the course of several days, as an "accident at work" He was deemed fit to work after a small compensation fee. Damian has since then been afraid of Genetics and dislikes its use. The ears and tail are fixed to him and irremovable because they are a part of him, actual flesh an blood, this however makes it impossible or incredibly uncomfortable to wear any form of exo suit helmet. damian after some time became quite fond of the ears and tail and opted out of corrective surgery.
to add some more context into him, he uses them as a basic sense to express himself and to be of use to him. his tail is usually used to hold something e.g. a cup containing non hot liquids or non breakable things such as stamps, basic tools etc. this however is temporary as he does not posses complete tail eye coordination so he has nothing more than basic motor functions within his tail. his ears usually represent his mood even if he is trying to hide it and twitch or droop accordingly. a down side however is that he is prone to some experiences of pain if incredibly loud noises are too close