Leanan Sidhe is requesting you to eliminate Apsaras in The Water Nymph quest in Shin Megami Tensei V. You’ll have the option to obtain this quest by speaking to Leanan Sidhe after being willing to listen to her if you accept The Spirit of Love quest from Apsaras. You’ll have a choice to make, and if you pick to side with Leanan Sidhe, you’ll have to take the fight to Apsaras back at her cave with her several demons.
You’ll be able to take this quest when speaking with Leanan Sidhe. You can find her Shiba Park, to the south of the Leyline, right next to Tokyo Tower.
You’ll likely encounter Leanan because Apsaras originally asked you to eliminate her. However, if you choose to hear her out, you’ll have the option to pick to go after Apsaras. If you choose to do this, you’ll have to return to Apsaras to the east of the Shiba Leyline, in the Netherlands.
When walking up to Apsaras, she will repeat that she wants you go after Leanan. But when you choose to support the other side, Apsaras will figure out you’re working for Leanan, and you’ll now have to battle her. When fighting Apsaras, she summons a trio of Agathion to her side, each level 12. Apsaras is level 16. You want to go after the Agathion first because they have Dia, so they’ll be able to heal during the encounter. The Agathion are weak to Ice attacks. Once you’ve defeated them, aim your sights on Apsaras. She is weak to Fire attacks but resistant to Ice damage.
Upon defeating Asparas and her group, she will flee from the scene. You’ll need to return to Leanan to receive your reward. She gives you two Stamina incense for your trouble, and she joins your party. She is level 17, weak to Light and Air attacks, but she blocks Dark attacks.
