“Naegissa is the High-Priestess of Nightmares and the Voice of Nerath. She’s the only one to be able to hear the Words of the goddess directly inside her mind without being overwhelmed by fear, distress and madness.
Her family has been follower of Nerath since the Ancient Times and was waiting for that day. When it came, the current scion of the first High-Priestess was Naegissa.
After the resurrection of the two goddesses, Naegissa was changed into a Crystallized. However, being the High-Priestess and the Voice of Nerath made her very different from the Nightmares’ army – she now have a very small fraction of Nerath’s power she just inherited and, compared to Nightmare Moon, Naegissa knows where the power comes from and can perfectly master it, especially since a goddess’ magic is way different from any other creatures’ magic (the mere essence is different, as a goddess’ magic is pure life-force).
To give a “ratio”, Naegissa’s magic abilities are now nine to ten times more powerful than Nightmare Moon’s.”

The Crystallized form of Naegissa is more impressive than any other Crystallized, being the High-Priestess.
While she was originally a batpony (her wings now being crystalline and a bit translucent are a bit bigger than an actual batpony pair of wings), she now has a horn looking like a dark-blue ice stalagmite.
Her navy peony fur is now lightly strewn by crystals, sometimes purple, sometimes blue.
Her eyes are really similar to Nightmare Moon’s, though she has a tribal crescent moon in her left eye.
She is horrifyingly calm, doesn’t express any emotion excessively and keep a stoic face.
Her perfectly made half-long stormy grey mane has some thin light blue locks, shining like diamonds. She has a very stylized bun, pierced with two long crystal thorns – one blue, one purple.
Her tail is quite long, having the same colors and locks than her mane.
Her hooves are totally crystallized (royal/dark blue), sometimes slightly glowing due to the power Naegissa withhold. She has a strange aura surrounding her, some sort of barely visible white smoke, like infinitely small drops of ice.
While she doesn’t make them always appear, she can create out of thin air two big dragon claws of crystal, floating around her, which she can control as her will.
She wears what remains of her High-Priestess cloth, though most of it is pierced by the several crystals coming out of Naegissa’s body. Now it is only an anchor grey vest old by a black jewelry which looks quite similar to the symbol she has on her left eye.