Castle Ironfist

In the Temple of Baa's central chamber, open the four doors in the order North, East, West, South (“NEWS”). Opening them out of order shocks you; each correct door gives a ‘click’ instead. The plaque hint: “As the winds blow, the seasons change, and only at the end of all can the doors be opened.”

The central chest holds the Bathhouse Key → Bathhouse 1 holds a Treasure Room Key → Store Room 1 holds the next Bathhouse Key → Bathhouse 2 holds a Store Room Key → Store Room 2 holds the Secret Door Key. Keep the Secret Door Key: it opens the wall behind the altar (your escape from the gong horde) and the ledge room holding the Chime of Harmony and a second treasure room. In the altar hall, walk in the wall water troughs to dodge the timed fireball trap.

On the ledge corridor above the altar room, click the unlabeled torch in the corner for a flat 5000 gold. Also grab the gong on the altar (sells for ~2000gp in Free Haven).

The chest in the room near the top of the long hall holds the Guild Key. Take it to the locked door in the east hall, but jump over the square tile directly in front of that door or a trap blasts you. Inside is Sharry Carnegie. The other chests here hold only junk (a worthless Prince of Thieves scroll).

Behind the big double doors a Veteran guards several ‘chests’ — only one is a teleport trap that randomly warps you elsewhere; the rest, including the one with Andrew's Harp and loot, are real chests, so just open them all. Hit the Veteran through the crack between the doors so he can't reach you.

Cast Lloyd's Beacon the moment you enter. The inner door needs Snergle's Chambers Key (from Snergle's Iron Mines in the Mire). Opening the final locked door (in turn-based mode) erupts a wall-to-wall dwarf swarm — recall the beacon to bounce back to the entrance, then grind them down in the open corridor. Take Snergle's body for Snergle's Axe; do not drink the black liquid in the barrels, and save before mining each gold vein (cave-in risk). Three bone piles inside each give one character a permanent boost: +5 Magic Resistance, +5 Poison Resistance, and +5 Might.

Work the switch chain: hit the switch behind the two west doors deep in the manor, then return to the start where the previously stuck left-room door is now open; wind around it, hit the north-path switch, then the final switch in the first fissure south of the empty well room. A new doorway appears in the big skeleton hall — save, then enter; running teleports you behind Corlagon (a Power Lich) with ghosts spawning behind you. Kill all, then disarm the trapped chest for the Crystal of Terrax. Use the well as a chokepoint (or Jump out of it) to fight Specters one at a time.

Endgame: ask Prince Nicolai about the Third Eye, recover it from the well northwest of the castle, and bring it back for Tanir's Bell. Carry the bell upstairs to the castle library and ring it to free Archibald, who gives you the Ritual of the Void scroll. Confirm the scroll is in your inventory before leaving — it is required for the good ending. Note: freeing Archibald drops your reputation, so train Light Magic Master (needs Saintly) first if any caster still needs it.