Art by Ramul over at DeviantArt: http://www.deviantart.com/art/Delirium-182939094

Abilities: Immense physical and mental capabilities.
Influencing dreams.
Influencing time (to a limited extent).
Shapeshifting.
Modifying the genetic and cellular level structure of organisms.
Influencing thoughts and actions directly and indirectly. Influencing the state of sanity directly and indirectly. Influencing feelings and desires to some degree.
Creating life from suitable materials if the conditions are right.
Three different types of breaths that can be used to cause havoc while in his three-headed dragon form: Poisonous / Toxic & Acid based breath (green / middle head in his three-headed dragon form), Cold / Ice & Water based breath (blue / right head in three-headed dragon form), and Fire / Lava / Magma / Plasma based breath. Taegan can produce different types of breath combinations as well (for example: combining flammable gas from the green head with the fire from the red head, causing and explosion. Or combining ice and fire from the blue and red heads to create a jet of steam).

Primary forms: Three-Headed dragon with multiple sets of arms, legs and wings Red, Blue and Green heads. Each head is directly affected to the following three states of mind / desires / ways of doing things: Destruction, Domination, or Madness.
A cloud made of darkness and unholy energies with multiple arms (usually six arms with four to five long fingers / claws in each) and six yellow eyes.
A humanoid with horns, long black hair, dark skin and two organic & sentient dragon shoulderpads / pauldrons (his two other heads from his dragon form) on each of his shoulders.
A black minion (a creature resembling a generic goblin, but smaller) with horns and a spiked tail ending in a mace/morningstar shaped tip. Between the horns, a flame alternating between the colours of red, green, blue and yellow is burning.
Other dragonic forms (a long serpent / snake like form with multiple yellow eyes along the main body and a single head that splits into three mouths with feeding tendrils located inside being a prime example).

Abridged backstory will be added at a later date.