Chateau d'Onterre

Chateau d'Onterre is a side quest in Dragon Age: Inquisition

"What exactly happened in the long-abandoned Chateau d'Onterre is a bit of a mystery. Perhaps exploring its darkest corners will uncover some truth - or treasures."

Acquisition
Obtained by entering Chateau d'Onterre.

Walkthrough
Head to the Formal Gardens (centre of the ground level) and use the Search function to find Codex entry: Sketch I of Chateau d'Onterre Interior which identifies the next location you need to find to solve the mystery of Chateau d'Onterre. The location of Sketch I is identified on the Sketch of Chateau Courtyard if you have previously found this.

Undead will start to spawn and will increase in number as you progress the quest.

Return to the Gallery (bottom right of the ground level) and head up the main staircase. Turn around to find the bust statue overlooking the staircase. Interact with the statue to find the next clue, Codex entry: Sketch II of Chateau d'Onterre Interior.

Head west through the library and north into the bedchambers hallway then the second bedchamber on the left. Interact with the painting to retrieve Codex entry: Sketch III of Chateau d'Onterre Interior. Retrace your steps back down the gallery staircase and up the stairs past the Servant's Quarters (top left of the map).

Through the Antechamber you'll find the upper level of the Ballroom and the next part of the puzzle under the lion's head statue on the other side of the dragon bones. Interacting with it will cause the dragon's tail to straighten and a note will be found on it.

Unlock the balcony on the bottom right side, defeat the undead and access the room behind the locked door to loot some notable items. Interact with the glowing box to gain a permanent increase of +10 to your Cunning attribute. An Arcane Horror will spawn in the Formal Gardens below. Defeat the demon to complete the quest.

Rewards

 * 967 XP
 * 200 Influence
 * 2 Power

Notable Items

 * Superb Ring of Staggering is found behind the locked door on the Grand Balcony.
 * A mosaic collection piece for the Invasion mosaic is also found in the above room.
 * The Arcane Horror at the end of the quest drops:
 * D'Onterre Crest Ring
 * Amulet of Power (Cole)
 * Enhanced Walking Bomb Ring
 * Superb Cooldown Amulet
 * Fire Rune

Codex Entries

 * Codex entry: A Torn Diary
 * Codex entry: Sketch I of Chateau d'Onterre Interior
 * Codex entry: Sketch II of Chateau d'Onterre Interior
 * Codex entry: Sketch II of Chateau d'Onterre Interior
 * Codex entry: Of Gods and Doubt
 * Codex entry: The Girl in Red Crossing (see Patron of the Arts)
 * Codex entry: From the Canticle of Threnodies
 * Codex entry: Superstitions
 * Codex entry: Lord d'Onterre's Journal