The Siren hasn't already charmed one of your heroes.

You have at least 2 heroes remaining in your party.

You have at least 1 hero not on Death's Door.

If it is the first turn of the round, and the following conditions are met, the Siren is guaranteed to use Song of Desire:

In addition, the Siren's charm is able to target invisible heroes. Note that if you flee the fight while a Hero is currently ensorcelled by the Siren, that hero will be lost. Heroes will be put in a random rank either right in front of or behind the Siren (while she pushes herself backwards one rank) and typically fight for the Siren for two full turns (taking minor stress damage for every turn they spend charmed) before returning to your control - they will, however, be placed in Rank 4.

Charmed heroes only have access to the moves on their bar and will move if they don't have a move they can use. The Siren's main gimmick is her Song of Desire ability, which allows her to temporarily mind-control one of your heroes. And, when at length the tide receded, jewels of the most magnificent grandeur lay scattered upon the shore. A small push was sufficient to send both into the icy waters. Before she could properly appreciate her position, I clamped down a manacle, chaining her to the leering idol. Under the blood moon, I lured my wide-eyed prey to the pier's edge. A fearful stirring at the edge of the torchlight betrayed a familiar witness and gifted me with malign inspiration. The pact struck, my new-found accomplices slipped silently beneath the brackish water. Their price was the delivery of an obscure idol and one other item of more troubling portent. In financial desperation, I struck a bargain with the ancient things that surfaced in search of sacrifice when the moon was right. Faithful as the tide, one precocious village waif made it her hobby to shadow my every errand. My lofty position wasn't always accompanied by the fear of office, and there was a time when I could walk the streets or raise a glass in the tavern without concern for molestation.

Darkest dungeon siren veteran team