First sorry for my bad english but I´m actually from germany and this is only a translation of my original post:
Ok first of all I´m going to describe the 10man instance.
In my opinion we never fought the real Arugal. The Arugal we killed in Shadowfang Keep and which got resurrected by the Lich King was only a puppet. A puppet which Arugal controlled from his true wherabout. Gilneas. The Lord over the Worgs of Azeroth has took over the land behind the Greymane Wall. Gilneas should be a zone with many daily quests, like the isle of Quel Danas. And on the end of the country in the centre of the destroyed capital of Gilneas lies Castle Gilneas. The Raid instance where players will face Arugal and his Worgen minions. I also made a 5man instance but I didnt´translated it yet. But the entrance of both instances are close together and they both belong to the same instance complex.
Years he has been waiting. Years he has been planning. Now the time has come to show the world the power of the true Arugal. They thought they had killed him. FOOLS!!! Those appearances were nothing more than useless marionettes. Now they shall feel his all-embracing wrath. Slowly he walked through the once glorious halls of castle Gilneas. It had been easy to convince Grenn Greymane. Soon he accepted that the worgen were the only way to vanquish the horde. Of course this was only a trick. The Worgen will vanquish the horde, but they will also destroy the alliance. After he had found Ur and neutralized him, he only had to get rid of Greymane, which was easy. There was only one problem left. The last survivors of Gilneas have recovered under the leadership of Grenns granddaughter Grena. But he knows that this problem also wouldn´t last for long. Now that he had it. His ultimate Weapon. This and the new pact with the black dragonflight will make sure that nobody can stand against his fury.
Something stirs in the south of silverpine forest. Worgen attack the villages of the Alliance and the horde. The Greymane wall has broke open. A new war is breaking lose and brave heroes, which have faced the dangers of northrend, are needed to face the threat of Arugal. The Alliance and the Horde have built to new villages to face the army of worgen. But the factions cannot forget their hatred and interfere eachothers attempts to set their feet on Gilneas.
But there is still hope. In the ruins of the capital city a new faction is rising. Under the leadership of Grena Greymane, the true heiress of the throne, the flame of Gilneas welcomes Horde and Alliance in their battle against the nightmares of Castle Gilneas. Because only together they will be able to face Arugal and his minions, which hide inside the castle of Gilneas.
First Boss and Thrash: The first boss is only a gearcheck so don´t be disappointed if he doesn´t have an awsome tactic^^
When you enter the instance, you find yourself at the big courtyard of the castle. On the left side lies the corpse of Neltharu (3rd Boss of my 5man instance) and there is a big army of people from Gilneas. If you talk to Grena Greymane she will start the event and the attack on castle Gilneas will begin.
Grena: "Warriors, Brothers! Tonight we will fight for our homes, for our families. We will show Arugal and his beasts that Gilneas is still strong. That Gilneas, the people of Gilneas have still thier own will. We forgot our old hatreds and forged new friendships. With the alliance and the horde we will claim back our country. This is our land and we will show Arugal that it was a huge mistake to set his foot behind the Greymane Wall. FOR GILNEAS!
Now Arugal shows up and laughs at the player. He sends tons of non elite worgs against the army. Now the Worgs and the Warriors of Gilneas fight for one minute. You can see Humans and Worgs falling under the attacks of eachother, only to move on to the next enmy to battle. There are some catapults which will fire at the castle walls. After one minute of fighting, the players can hear a big bang. Now Fenros breaks down a wall on the side and runs on the battle field. Fenros is a huge Worg(similar in size to Malygos). Grena now calls the army back and Fenros kills the half of the npc on the battlefield and then retires. After Fenros has disappeared Grena will talk to the party. She will tell you to go through the hole in the Wall into the stables of Fenros, while her warriors will try to break into the castle through the wastewater pipes.
When you walk through the hole you´re in a big stable. There some boxes on the sides and the hall is lightened by burning corpses. The hole is guarded by a Worgendestroyer and a Worgenelite. On each side of the stables a Stablemaster of Fenros patrollers and there are 3 groups containing one Worgendestroyer, two stable boys of Fenros and two nighthowlers.
The gate which leads to the next room is guarded by one Worgendestroyer and one Worgenelite. In the next room there is only one group containing one Worgenelite, one Woregendestroyer and one Stablemaster of Fenros. Throught the floor which is only a grid you can see some Warriors of the flame of Gilneas in the wastewater pipes fighting against Worgs. They will kill the worgs and move on the get deeper in the castle but will shout to you to also go on. After another long corridor the party enters the room of the first Boss, Fenros.
Worgendestroyer: 260k Life Points
5k Damage on tanks. Attackspeed: 2
Destroying Punch: Hits all targets in melee range for 100% of their Hp. 4sek casttime.
Stablemaster of Fenros: 200k Life Points
5k Damage on tanks. Attackspeed: 1,7
Call Worgen: Calls two nighthowlers.
Call Fenros: Calls the first boss Fenros. He casts this if he lives longer than 40sek.
Nighthowler: 230k Life Points
6k Damage on tanks. Attackspeed: 1,8
Angry Howl: Silences all players in a range of 40 meters.
Angry Bite: 3 Players get a debuff which deals 5k damage every 3sek. This debuffs disappears when the Nighthowler is killed.
Stable boy of Fenros: 170k Life Points
4k Damage on tanks. Attackspeed: 1,6
Curse of Worgen: All damage dealed to you by worgen is increased by 100%.
Healing Hand: Heals a target for 30% of its total health. Interruptible.
Thunderclap: Hits all players for 10k Damage.
Worgenelite: 350k Life points
7k Damage on tanks. Attackspeed: 1,8
Clawattack: Hits all players in the raid for 50% of their total health.
Shadowclaw: Hits a random player for 8k damage and deals every 2sek 3k damage to this player for 10sek.
All Mobs except the Worgenelite and the Stablemaster of Fenros are corwd controllable.
Raid Boss: Fenros ,the big worg.
5,5 Million Life Points
A Fight with contains only one Phase. The Boss is tauntable.
10k Damage on tanks. Attackspeed: 2,6
Mangle: Deals 8000 damage to the tank and leaves a dot(Cursed Bite; Curse) which deals 8000 damage every 3sek. This dot is removable.
Schadowbite: Deals 8000 Damage to the tank an increases damage taken by 1000% for 29sek. It also leaves a dot which deals 10000 Damage(with the increased damage debuff) every 4sek for 16sek. He casts Shadowbite every 30sek, therefore you need two tanks for him.
Shadowsouls: Every 5sek Fenros shots a shadowsoul to a player which not stands in meleerange. It requires 5sek to hit the player and will follow him even if he switches places. This player will deal 3k damage to himself for 5sek and 6k to every other player near to him(10 meters). The room is big enought to spread out so that nobody is to near to any other.
Enrage: After 4min Fenros enrages and increases his damage by 1000%. Also he will shoot Shadowsouls every second. That means a total raid dps of 23000 is needed to beat the enrage Timer.