Heroic: Trial of the Champion

Ok, Let me clear up this instance a little.
Note: This guide is Alliance only!

You walk in by the most northern entrance.
After you are in, everybody jumps on a one of the horses along the side of the arena and talk to the guy in middle, he will start the event.

You fight on horses, Identical to the daily "Amongst the Champions" in whole 1st round.
Wait a while, and 12 NPCs will walk in, 3 bosses and 9 trash.

1st round:
Trash will attack in groups of three till they all are dead.
Then the bosses will come, It doesn't matter in what sequence will You kill them.
Note: Should you die, run to the side and jump on a horse if there are some left ASAP
Healers Advice

1,5th round:
The 3 bosses regenarate to their full health and you have to defeat each of them. I strongly suggest killing warrior first (MS's the tank), It's an orc rider for Alliance.

2nd round:
Get your drops from the chest in the middle and start the 2nd round by talking to the guy in the middle.
You can get one of the two random bosses, along with 9 Trash in 3 groups (Can be killed simultaneously, but killing the last one will pull the boss).

Eadric the Pure or Argent Confessor Paletress

Eadric the Pure is quite easy, turn your back at him when he starts to "emanate light". When he does his second spell (Throwing his hammer) It's possible to catch it (by right clicking it probably) and throw it back at him (If you fail to catch it you get around 15k damage done to you). Targets only one random person.

Argent Confessor Paletress is quite harder, She summons a random NPC (possibility of getting (but not limited to)Hogger or Algalon!) with 362k HP behind random player. I suggest dealing with it (you have to anyway, she's immune to everything as long the NPC is alive). She does not do any more spells that you would need to be aware of.

Should you succeed, loot your reward (chest in the middle) and talk to the guy in the middle again, this will start the round 3.

3rd round:
The Black Knight

This fight consists of 3 phases, which change after you defeat The Black Knight in each of it's form.

1st phase:
Human(?) form(276k hp): Does not do lot of damage, no spells need to be mentioned.

2nd phase:
Skeleton form(276k hp): Ok, this is quite harder. He will summon an army of ghouls with around 36k Hp, which I suggest to AoE. But beware! Black Knight can make the bodies explode so better keep away from them.

3rd phase:
Spirit form(276k hp): Prepare for a big chunk of healing. He will cast a debuff on everybody, making them get 5% more magic damage done to them every few seconds. He will also keep debuff on one random player changing each (around) 10 seconds, causing the target to take 200% more magic damage.
He casts a volley of bolts (which are shadow I think), not hitting that much, but they are deadly for the debuffed player.

If you managed to kill him, Grats! Loot the chest and enjoy your new items :)

Post-scriptum- I strongly suggest trying this instance in a normal mode for 1-2 times before going into the heroic.
Post-post-scriptum- Healers, prepare to give out a decent chunk of healing, this is an instance that shouldn't be treated like the other "easy" ones.

I will try to update this guide :)

I cannot get the achievement...I have tried three times now...zultore and confessor paletress never show up...don't know what I am doing wrong at this point...I did it three times because I thought perhaps the combatants change up but alas they do not

tried it again today and got those whom I was missing...got my achievement as well so I guess then the secret is they do not all show up in the same challenge but you must go back again and again to get them all - luck of the drawl - you will only get three in one shot.

Argent Confessor Paletress is quite harder, She summons a random NPC (possibility of getting (but not limited to)Hogger or Algalon!) with 362k HP behind random player. I suggest dealing with it (you have to anyway, she's immune to everything as long the NPC is alive). She does not do any more spells that you would need to be aware of.

She will also summon Heigan the Unclean. But you don't have to safety dance =)