Maiden of Virtue is the third boss of Karazhan, one of the easier fights in the dungeon, and generally is more about good healers as well as a high-mitigation capability tank than it is a DPS burst fight unlike some others.

The boss herself is basically a big paladin; she uses consecration, silence, holy fire, holy wrath, and repentance.  In general your main problems come from big mass stuns via repentance backed up by holy wrath and some face-smashing.

Consecration

From start to finish of the fight Maiden will throw down a consecration directly on the area where she stands, this is also re-applied should you move her.  Anyone standing in the range of the effect takes around 250-350 holy damage every three seconds, this is applied
throughout a 15-yard range from wherever the boss stands.

Finally, anyone hit by the consecration/standing in it is silence for a partial second every second, making anything but instantaneous spells impossible.

Holy Fire

This is the main spell cast throughout the fight along with consecration, the Maiden will randomly target ranged raid members and nuke them for around 2.5-3.5K damage.  After the player is hit with this a DoT is left behind that is capable of being dispelled as magic.
Take care of that DoT or you’ll find a lot of your weaker players dropping quite easily.

Holy Wrath

Somewhere around every twenty seconds or so Maiden will cast Holy Wrath on a random raid member, this hits the initial target for 2000 damage and then will jump to a target within 7 yards.  This chains the spell from player to player increasing the damage done each jump by around 1000, basically don’t group up to closely.

For melee DPS/tanks on the boss have them stand in a formation dragged out to the maximum range wherein they can still hit the boss, having all who can stand seven yards away from one-another whilst still hitting the boss.

As soon as Holy Wrath is cast you can move anyone unable to fit into this formation back into combat.

Repentance

Maiden will periodically cast Repentance throughout the fight, this deals around 2000 holy damage to every member of the raid as well as temporarily stunning them for ten seconds.  Any damage dealt breaks the effect, this means that the Main-tanks stun will be broken should he have agro at the time.

There are a number of ways to get around this, as having your main-tank without heals for ten seconds is very painful especially for newer/lesser-geared raids.

Obviously you’ll want to stack as many HoT’s on the tank before repentance is cast, with enough of them going the tank can simply through up a last stand/shield wall, etc. to stay alive.

Another effective workaround is to have a paladin throw up Blessing of Sacrifice in time with the repentance, allowing him to take damage as the spell is cast and therefore break the stun, meaning you have at least one healer up.

Finally you can have your healers either A: Run into the consecration effect seconds before repentance goes off to break the effect, or B: Have the main-tank move the Maiden over to the healers and therefore once she throws down consecration it’ll break them out of the stun.

The Pull

This fight can simply be started by having the main-tank charge into the room where Maiden waits, also I suggest you keep her positioned in the middle of the room for the fight as to prevent any line of sight issues.

The Fight

Well, the fight is actually relatively simple and has pretty much been explained already.  It’s all about countering Maiden’s various abilities and reacting as needed to prevent anyone important from going down, of course if you can keep everyone up then do so.

One good policy to put into action is having the melee DPS run out of the consecration and bandage as needed, keeping the healers capable of saving mana for when it’s really needed.  Keep the tank up, put up a steady DPS, and have on the ball healers and this fight should be easy enough.