Somewhere in the past, Sylphy married to Regulus Corneas, becoming his 184th wife.

Eventually, Regulus traveled with his wives to Priestella, where he wanted to marry Emilia. However, he ended up being confronted by Natsuki Subaru and Reinhard van Astrea.

During the battle, Emilia tried to ask Sylphy for a way to save everyone and stop Regulus, to which she responded that there was no way. Sylphy was ready to kill herself, but Emilia didn't agree with such solution. The wives, including Sylphy, were frozen by Emilia's magic, so that Regulus wouldn't be able to use his authority. After Regulus Corneas was successfully defeated, Emilia freed all the wives.