A Dracolich sometimes appears as a skeletal or semiskeletal version of its former self, with glowing points of light in its shadowy eye sockets.
Physiological observations of the Dracolich are in direly short supply. Thankfully few of these creatures have existed. A sage was, through diplomatic request, able to gain temporary access to the only known Dracolich to have been taken “alive”: Daganth the Eclipse, held in highest restraints within the Elven temples of the Western Empire. The beast was terrifying even in captivity and his consciousness subdued. It took several attempts before they were capable of remaining in the room for more than a few seconds without fleeing in fear.
The physical body of a Dracolich can be an indicator of its power and age, with new Dracoliches still having flesh yet to rot. Once the soul has been removed from the body, the body is most certainly dead. As such, without proper physical care and magics, (both are required as mundane means only go so far) the body begins to rot and decompose. While there are the incredibly rare reports of Dracoliches who have maintained their body carefully throughout the ages, the overwhelming consensus seems to be that with great age comes little motivation to do so. Thus, most Dracoliches allow their body to rot until they are little more than great skeletal figures.
The decomposition process is what makes determining the original scale color of the Dragon difficult. One must work from clues based on skeletal shape, size, and wear. This can be terribly misleading, however, as time and personal habit can lead to odd markings and alterations. While conceivably a Dracolich may be of any age at the time of conversion, the experienced required to undergo the transformation means that most are skeletons of great size and age, the wyrms of their kind. This makes most of the beasts quite large, the size of several buildings in length and height, though obviously without much of the weight from organs and tissue. It maintains the great claws of the Dragon species, as well as the mighty teeth.
Though the beast has no eyes, it appears to have no trouble seeing. In fact, it seems capable of discerning friend and foe in the pitch black with ominous green light that emanates from the sockets. For all accounts and purposes this is completely cosmetic in that the creature has no need of the light. It is, however, incredibly unnerving. They are also capable of hearing, despite their lack of ears. Speech is possible through the use of magic. Mundane means no longer serve as the throat has long since turned to dust.
The Dracolich has no need to eat, breath, sleep, or even move unless it so desires. This makes its lair options quite varied, and allows it to choose according to its purpose. Mountain caves, old labyrinths, ancient forests, even the bottom of the ocean if it serves the beast's needs.
A truly fascinating aspect of the Dracolich is the presence of the Dragon's Breath, despite the creature's lack of inherent lungs, throat, or indeed even the need to breath at all. I believe that this is a kind of sentimental attachment to the existence of its living counterpart and the deep seated connection to its being and type. A Dracolich is quite capable of emitting terrible and powerful energies from its jaws, usually in the form of ghostly fire or necrotic black energy. However, some Dracoliches do not seem bound to this particular breath, as the Dracolich Saphira is said to have emitted jets of acid during the Wars of Myth in the Second Age. I am told that Daganth the Eclipse does not have this capability. This would suggest that the magical nature of the beast makes them capable of learning to augment this breath to suit their needs if they are sufficiently powerful and inclined to learn.
The body of a Dracolich is far from indestructible, though it is indeed incredibly resilient due to the powers that move it. Should the body be destroyed, the bones cracked and scattered to the point that the spirit of the creature can no longer maintain the form, it crumbles to dust. This is not the end of the beast, however, as long as the phylactery remains intact. In time, the soul crafts a new body to inhabit near the phylactery so that the beast may continue its unlife. Human variations of liches can take over a week to reform a physical manifestation. It stands to reason that the body of such a massive creature would take longer, possibly even months, before it is capable of being inhabited once more. During this time, the essence and soul of the Dracolich is bound to its phylactery, unable to act upon the world. This is when the creature is most vulnerable. As a result, the phylactery of such a creature is always well hidden and guarded.
The physical weaknesses of the Dracolich are few and far between. Being once Dragons, their bones are incredibly sturdy and difficult to destroy, and they retain the powerful energies that cause spells to falter in their presence. The addition of the... I reluctantly say “benefits”... of undeath make them even more resilient. The Dracolich does not have any of the valuable organs, the small breaks in the scaly hide, or the dependency on sensory organs that adventurers have used in the past to assail Dragons. The beast does not fear the lucky axe blade nicking an artery, or the well placed dagger piercing the eye. The necromantically infused bones will shrug off all but the most grievous of injuries and the lack of pain means that even these will not cause the beast to falter. The one true weakness these abominations seem to fear is the power of the Divine, and the life giving positive energies it brings. Even this is a difficult weapon to wield, as the beast is capable of attempting to stifle these energies to prevent them from affecting it. Daganth himself emits a horrible aura, and his lair was desecrated to slow the advance of the Elven Clerics that assaulted him.
The appearance for most of them, however, is the same as when they were alive. The only true way to really know if they are a Dracolich is if you ask them or notice they have a best friend wizard that they seem bonded to. A Dracolich has a special connection to the wizard responsible for their transformation if the Dragon consented to the ritual, and they often live within a few miles of one another, aiding each other if one is attacked.