This is Tiamat, a dragon goddess (or, perhaps, a goddess dragon) in the Shades of Grey setting (somewhat inspired by the D&D Tiamat, I admit). She is often called Dragon of Chaos and Night Dragon. The former name was given to her for creating a plethora of different monsters, the latter due to her pitch-black scales that reflect light in such a way she melds with the starry sky. She and her brother, Bahamut - Dragon of Order or Day Dragon - are actively involved in the affairs of the mortal world, unlike most other dragon deities, and thus are known not only among dragons and most devout scholars. Tiamat is usually considered an evil deity by lesser races, but dragons themselves hold both her and her brother in the same regard; then again, they view them as dragons first and deities second, anyway. Tiamat does not seem to have a particular domain, travelling across the Outer Universe instead, often taking different appearances. She takes great enjoyment in sowing chaos and causing things to happen, often instigating conflict and strife. However, sometimes her actions may cause things to change for the better - which is fine by her, as long as she gets to have some fun. Also, she has a great fondness of seas, oceans and other large bodies of water - which is somewhat fitting for a chaos goddess.
She is also greatly amused by suicidally stupid adventurers that sometimes try to challenge her.

This particular rendition of Tiamat © me, I guess :3
 siegfriednox

P.S. She has mind bullets. And breaths black and purple fire.