Should I Kill the Succubus in The Witcher 3?
Killing the succubus in The Witcher 3 gives you a mutagen, a trophy, and a clean contract resolution, while sparing her fits a merciful playstyle and can unlock extra dialogue. The choice appears most famously in the Novigrad contract Deadly Delights. Because it has no major impact on the main story, the best path depends on whether you prioritize loot, roleplay, or optional content.