So far, Luna has appeared in all three Witch Spring games; she was a supporting character in the first, the main character of the second, and makes a cameo in the Light/True paths of the third.
Witch Spring 2Edit
Witch Spring 3Edit
At the end of Chapter 4 (Light/True path), Luna and Pieberry appear in Derkarr. Pieberry defeats one of Regal's Ancient Dragon reinforcements, to Luna's annoyance, and she's about to defeat the remaining dragon when it is blasted by Eileen's Ecarr Vertel.
Luna and Pieberry teleport to the main scene, impressing Eirudy as they didn't even need a magic circle to do so. After being mistaken as Derkarrian deities who managed to stay hidden, they inform the party that the witch hunts in Vavelia have officially ended. Regal is shocked, saying that even without the Pope, that they shouldn't be able to get past "him." Johannes asks if he meant Jude, to Regal's shock, and Pieberry exclaims that they had come to tell them about him.
Luna informed the group that Vavelia's Temple Lords had revived and destroyed Jude, who was behind the witch hunts. Monnet then speaks up, noting that she could no longer sense Jude's magic on the Dragon's Nest. With that, she delivers a fatal blow on Regal as punishment for forcing her fellow dragons to sacrifice their lives. The two Vavelian deities are shocked, but cannot do anything to stop her from leaving, and are unable to save Regal's life as neither have expertise in healing.
The two are not seen after that, so it can be inferred that they returned to Vavelia shortly afterwards. However, Eirudy mentions Luna in the ending, saying that Luna told her "something called a kiss feels even better."