Find the knight and grab some bonus loot in this short walkthrough.
Darks Souls 2 guide: Crown of the Ivory King - Knight of Eleum Loyce location
In the hallway you'll find two Ice Golems, a Frozen Soldier and a Retainer Mage. Run past the mage and the soldier, and only the soldier will follow. Kill the soldier and use ranged attacks on the two Golems without the mage seeing you. Finally, kill the mage and open the gate at the end.
When you enter the room, the Knight of Eleum Loyce that you need in The Open Chaos area will teleport to the Cathedral.
Go up the stairs and open the door at the top. This is the locked door that you found immediately after the boss fight with Aava, the King's Pet. Open it now for a shortcut to the Cathedral if you need it.
Go back down the stairs and into the lefthand hallway, just outside the room where the Knight of Eleum was. There are three Flame Butterfly items at the end of the hallway. Examine the right side of the hallway near the middle and you'll open a secret passage to the bridge below.
When you drop down you'll see a Frozen Soldier on the right on a balcony. Take it down with ranged attacks, then go down the hallway under the opening. Near the end you'll have to fight two Rampart Golems before heading back across the bridge to the other side.
On the left is a Frozen Warrior on the stairs. Kill it, go up the stairs and you'll find a chest with a Fire Clutch Ring. Drop down and you're back in the room where the Ice Golems, Frozen Warriors and Retainer Mage were earlier.