I am Setsuna | Kir's Legendary Spritnite: Doom

Go to Hiddbury with Kir in your party and go to speak with Hydor in his tent. A conversation will occur, he will tell you that there are some new travelers have arrived there. Head to Spritnite Pillar at the north of the village to meet them.

There, another conversation will occur and you will learn that they are Rare Bloods. And Kir's brother, Tor, helped them set free from the humans who tortured them. This conversation is quite long. Then, head back to the village to meet Hydor and the two of the sisters again. You have to find Tronne and have to go back to Spritnite Pillar. Make sure you save your game first!

Unfortunately, the news that Tronne went missing is not true. The sisters then attack you for the sake of revenge.

Syg is the healer, she can revive and cure other sisters. So target her first. Tronne is more to magical attack and her resistant is quite high, also immune to most magic. Quotra is good in melee attack but weak against magic, if you have any strong magic or combo that can deal high damage, go for it.

After they are defeated, they will vanish in a thin air and you will obtain Doom spritnite. Also, you will get Darkmoon, a new weapon for Endir, that has shadow-elemental attack.