The spirit of the sacrificed Leporidaen is nowhere to be seen. It wasn't wearing the symbol.
Spoiler for what happenned to the spirit while the wall was still up an Stella couldn't see in: (Highlight or hover over the text to view)
It was devoured by the creature. The soul was "moved on" to the next plane of existence.
((without doing the dice rolls, basically this is what would probably happen. If you want to do dice rolls to contest this, let me know.))
Stella's spirit vines are shattered by the creature easily. It is clearly far too powerful for her to defeat.
Estella isn't a spiritualist, and in fact, her ability to work with Magem is inhibiting any spiritual ability. Nevertheless, her attack on the creature is far more effective than Stella's. The seeds soar through the spirit and land on the ground. But they do take root, and grow quickly - feeding off of the energy in the room. The growths are difficult for the creature to move through.
Ybrect says, "Spirit of Fertility, in the name and traditions of Grandel the Wisest, I command you to arrest your violence immediately." The sound of her voice echoes loudly in the Spirit realm.
The creature hesitates and turns to Ybrect. "I am neither beyond my bounds nor accords. I was summoned and my cage crumbled." Gesturing around her, the creature says, "This is my home. This is my fiefdom. I have taken nothing which was not mine. You have no right to interfere."