This is genuinely the only boss where I feel there is no strategy involved. In my second attempt she stole one of my Grave robbers (tried to use a dodge comp), which again I had to stun, and then proceeded to steal another one, leaving my party in complete shackles. I was forced to stun her and after it wore off she immediately stole her again, proceeding to kill the Plague doctor and putting another ally at death's door while applying blight to all of them. On my first run it stole my Shieldbreaker, which then proceeded to hit my backline for 41 damage (instantly putting my Plague doctor at death's door). On my second playthrough I've lost 2 full parties to this boss, twice in a row for it would steal one of my damage dealers and proceed to beat the ♥♥♥♥ out of my team with them. It's like the opponent has suddenly gotten a Skiver with shroud. You will deal significantly reduced damage for 3 turns while taking an immense amount in return, with a priority target you cannot focus. These champions are placed into the first spot severely limiting your options to stun them (which results in them returning to your side, stunned - if it applies). If it steals the main damage dealer (like a Helion or Shieldbreaker) you're in a massive lose-lose situation. This is the bosses gimmick and by far her most dangerous move. The only thing to watch out for her is her 'Song of Desire', which steals a party member for 2 turns. The boss itself is not dangerous at all and has no offensive attacks to watch out for.

Cleave bosses are at least countered by riposte, but the Siren has no obvious strategy at all she's just a complete high- or low roll boss that either wipes your entire team without any effort, or does practically nothing. This boss feels like there is no strategy involved in any way.

People cheesed this by bringing the Antiquarian and always having her nabbed from your team - which would be of absolutely no harm. We all knew that previously the Siren would, with 75% certainty, take the lowest resist party member.

Siren fight darkest dungeon