With Flickering Heart is a side quest in The Witcher 2: Assassins of Kings, available in Chapter 2 on Iorveth’s path. The elf Ele’yas tells Geralt that young elves and humans are being murdered in Vergen; the bodies turn up near a burned village at the mouth of the gully and are buried in the dwarven catacombs outside town.
A smell of sulfur at the village and the state of the bodies point to a succubus. One victim carries a stolen book of Dandelion’s poetry, so Geralt and Dandelion meet in the burned village at midnight, where Dandelion’s verses draw the succubus out. She claims that Ele’yas, a jealous lover, is the killer, while he denies it, and Geralt has to decide whom to believe with little hard evidence either way.

