The Final Showdown:
So you got through the running around, the Demonic Prison, and the Circle of Five. All that's left now is one last little fight to fully unleash the power of your Champion Weapon. Here is the strategy you will need in any realm on classic, standard, and coop servers.
First, what to bring? 2 tanks, 2 healer-types, power regeneration of some sort, and some damage. Now team up with two other groups to get there.
Second, get to him. Clear the aggro until you get to the long corridor. Hug the right hand wall to avoid aggro from the room on the left. That leaves you one last room to get through with a little bitty obstacle in the way. A room full of baddies with Legion standing right at the door to the Instanced Dungeon that holds your fight. Stay to the left hand side of the room, clearing an alcove, then moving on to the next. Pull the mobs around Legion until the steps are clear, then zerg the big guy till he cries for mommy. The group that gets the last hit in gets his one time drop, an excellent jewel.
The alternative is to just SOS through Legion, open the gatem and hop on in. Remember, it is an ID, so 1 group at a time.
Once you enter, buff up and clear the red aggro on the walkway, now circle around the rocks lining the unholy temple and pull the red cons one at a time from around the end boss. Make your way back to the end boss.
Now you just kill him.
Healers stay back on the rocks, drop a power font if you have it. Start hitting him hard, tanks stand on the edge of the inner pit, do not /stick him, just stand their and do your thing. This will insure healers have LOS. Casters get barely inside the outer rim of the temple, just enough to be able to cast on him.He hits like a beast, has AOE DOTs, bolts, and AOE bolts. He is not immune to magic, but resists a lot. Just keep spamming those spells. At the beginning of the fight, dump your RAs on him... TWF, NM, ST, whatever you got. Do it now, they'll recharge by the time you need them again, trust me.
Now comes to his little trick, the shades. When you knock him down a bit, he will spawn a shade of one of the Circle of Five. You guessed it, he does it 5 times. As soon as he does this, stop fighting him. Kill the shade. When you are done killing the shade, you can go back to the clerics and rest. Take all the time you need. Start over.
After you kill the last shade, just beat him down. Your RAs will be back up. Use them. Then it is a simple matter of collecting your one time drop and hopping through the light in the middle of the temple, which leads back to your capitol. Talk to the King, then the illuminator, then the weaponmaster. Enjoy your completely unlocked Champion Weapon, oh, and the 7 bubs of CL exp the last fight is worth.