The Tenebris Somnia first boss is Obscuratus, a candle-headed figure in the candle arena on Floor 2. It is invisible while any of its candles are burning, so put them all out and attack only in the dark.

How to start the Tenebris Somnia first boss fight

  1. Take the Mop Handle out of the bathroom that the Devora poster puzzle opens.
  2. Return to Sanguis's bedroom on Floor 2.
  3. Insert the Mop Handle into the rectangular slot beside the window and operate it.
  4. The blinds close, and Obscuratus starts the fight.

Check how much ammunition you are carrying before you begin. This is where you spend your first rounds, and ammunition is scarce for the rest of the game.

The fight itself

  1. The boss is invisible while any candle in the room is still burning.
  2. Run to each lit candle and interact with it to put it out.
  3. Only when every candle in the room is out does Obscuratus become visible and vulnerable. That is the only moment worth attacking — swinging at the invisible form just wastes ammunition.
  4. Attack it in that window.
  5. When it relights the room, start extinguishing again. The relight is preceded by an area attack, so pull back the moment the candles start coming back rather than standing in the dark waiting.

Beating Obscuratus with the wrench only, with no firearms at all, unlocks an achievement. It is a natural first boss to practise on, because the wrench is the weapon you start with. Where the Red Candle and the Lapis Fictus Pill land afterwards is in the item locations list.

After Obscuratus

  1. Inspect the remains and take the Red Candle and the Lapis Fictus Pill.
  2. Combine the Red Candle with the Lighter.
  3. Use the lit candle in the elevator to unlock Floor 1.

The route from Floor 1 to the finale is in the walkthrough.

A second Red Candle shows up much later in the game, in the Desiderium chapter, where it falls from Julia's statue and lights the stairwell blocked by the red symbol.