From the entrance, turn right and follow the hall to a room with 3 stained glass windows. Break the one straight ahead and go up the stairs. Keep going straight at the 3-way intersection, coming to a room with a bridge over lava, flanked by cannons. Run across the bridge quickly to come to "Eidolon's Switch-Throwin' and Precision-Jumpin' Ordeal".

Go forward, down the narrow stairs to a room with stairs going up to a balcony. Go up the stairs and hit switch #1 to the left. This will open two doors underneath the balcony.

Drop down and hit switch #2 in the alcove to the right. Go back up to the balcony and go up the narrow stairs on the right. Jump across to the small shelf. Turn left and follow the stairs to a room with an uneven spiral staircase. Hop down and hit switch #3, drooping you down. Take the stairs beyond the spider back up to the spiral stairs. Climb to the top and hit the floor button, dropping a platform outside.

Step off the edge and return to the main room. Jump across the two pillars flanking the main door and then to the small shelf on the opposite wall. Follow the hall to a room with a tightrope over lava. Run across the tightrope and hit switch #4.

Run back across, return to the small shelf, and jump to the ledge on the left. Follow the path around and upstairs to a room with a box in the middle. Hit switch #5 to lower the box. Ride it down and turn to face switch #6. Jump across and hit it, completing the ordeal.

Return to the 3-way intersection (past the bridge over lava and cannons) and go left. Come to a room with stairs on the left and a pillar on the right. Go up the stairs and come to a room with lava and more stairs on the right.

Go up the stairs to the small balcony. Carefully drop to the lower ledge below the balcony. Hit the switch in the alcove to raise the bridges to the corner platform in the lava. Go up the bridge and throw the switch to unbar the door at the top of the stairs.

Go through this door and take the stairs up to the left. Walk up to the bars to open them. Come to a room containing a lava pool with a small platform in the middle. Walk the ledge around the parameter of the lava and throw the switch on the other side. Hop onto the platform and ride it up.

Follow the hall to the bars, open them, then hop across to the top of the pillar to get the Soul Key. Drop down and retrace your steps to the door leading to Eidolon's Lair.

Enter and face Eidolon. Do you think there's still a chance you two can sit down, have a beer, and talk things out? Probably not...

The final test is left to you... remember that the Chaos Sphere grants Eidolon the power over life and death. Use this information wisely.

Another good tactic is to use Eidolon's sluggish speed to your advantage. He cannot get to you if you stand directly behind his shell, but beware his toxic slime trail. Good luck, and don't cheat.