Thyrinar

Thyrinar is a elite twilight dragon located in The Nexus. He is fought while on the quest Through a Glass, Darkly, part of the questline to obtain Dragonwrath, Tarecgosa's Rest.

Fight
Thyrinar starts the fight with about 199k health (which is half of his health bar; clearly Tarecgosa softened him up for you)

Thyrinar has two main abilities
 * Twilight Blast (14-17K)
 * Twisting Twilight (channeled beam that pursues the player and creates a trail of fire)

Thyrinar bombards the player with Twilight Blast as his main attack. At intervals he channels a Twisting Twilight beam attack. The player should run away from the beam and avoid boxing themselves in with fire. The fire does fade after a while.

If that were the entirety of the fight this would be trivial, but adds run up the ramp at irregular intervals. The adds have around 77K health. They are oblivious to the player while they are running up the ramp, but once they reach the top of the ramp, they attack the player. Ideally the player should kill the add before it reaches melee range. The Twisting Twilight phase often frustrates that goal, since adds and Twisting Twilight sometimes overlap.

The add's abilities include
 * melee (5K)
 * Fire Nova (less damage the farther away you are)
 * counterspell (includes a spell school lockout)

If you end up with 2 adds alive at the same time, you are probably doing it wrong.

While you are close to Tarecgosa you get her healing/mana buff which can be the difference between success and failure for weaker players.

Thyrinar will not perform Twisting Twilight if the player is too far away (the bottom of the ramp is too far away). However, the player will not have Tarecgosa's buff, nor will he be in range to blast Thyrinar.

This fight is unlike most raid fights (because in raids you have other players to support you). It is probably closer to a PvP battle or Faction Champions. You will find yourself digging through your spellbook for spells that you rarely use.

If you are regularly taking damage from Twisting Twilight or the adds, you will probably lose the battle unless you outgear the fight.

Special class notes
Since mages lack a way to heal themselves, Thyrinar buffs himself with HoT they can steal.

Priests must dispel the HoT off Thyrinar.

Moonkin, make sure your Typhoon is unglyphed so you can exploit its knockback. Adds can not be knocked into the chasm.

Enhancement shaman, respec to Elemental. This quest is designed to exclude melee classes.