Them
Them are a species of demons that have been evicted from Hell to make room for the influx of incoming humans. In order to hide from mortals, they use magic to make most humans believe they are regular animals or in rare cases, other humans. Though they vary in features, all are four-limbed, capable of walking bipedal or on all fours, and have "hoods" with feathers typically sticking out. Hellborn Them (first generation) are truly immortal due to being lesser fallen angels or corrupted human souls, although can be killed if properly exorcised. Earthborn Them (second generation and further) have more distinct aging periods but still live for upwards of a couple thousand years and can be killed through decapitation or exorcism.