during the Reaping Ritual before last, a mysterious circus came to town to put on a performance (Cirque ad Infinitum: Io, Lin, Ran, Arika, Connie, Berinhard)

and for the first few days it was just fun cute carnival shenanigans, but when it hit the day of the actual Reaping Ritual and the powerful spirits of the season (Trick and Treat) showed up, something terribly wrong happened. They were captured, and suddenly people at the carnival were disappearing too. It seemed like the Cirque was actually evil and they began to turn into horrifying versions of themselves.

But it turned out, for years they'd been plagued and manipulated by this demon named "Veles". When the oracle Io was a young boy, he started seeing horrific visions of bad things happening to his friends that no matter how many times he prevented, more visions kept coming. That's when Veles revealed himself to him and made a deal that he'd make them go away and keep his friends safe IF he did him a favour... and that favour led Io losing his eyes and being possessed by this being. So for years he'd been using Io and the cirque to carry out his evil plan to gather souls. He promised he'd stop hurting people and finally leave the cirque alone IF given the chance to meet Trick and Treat.

Io, who'd been dealing with him for years, knew he was planning something, so he set up some traps to try to stop him once and for all... Which is why when things went TERRIBLY wrong, the members of Voltra were able to step in and help save the cirque and save Voltra.

(There was also a strange and mysterious exorcist, Smolkie McMoy, who showed up to help you. Turns out he wanted to adopt Io when he was a boy but was unable to, and felt guilty for what happened later on. He died trying to stop Veles.)

REAL ACTUAL TL;DR Veles is a demon Volties helped defeat and he's salty af at Voltra and obvs, the Cirque