Tree of Savior is a free to play MMORPG available on Steam. You play as a hero on a journey to search for the goddess in a world of chaos. One of the level bosses you might encounter is the demon lord Helgasercle.

This cosplay is by Cowbutt Crunchies, the photography by Mineral Blu and it was shared to Reddit.
The amazingly named Cowbutt Crunchies are a cosplaying couple. They make expert use of Tumblr to show off their final builds and clever use of Patreon. Backing Cowbutt on Patreon is designed to help you get better at cosplay, giving access to the couple’s own tutorials and even commissioned slots.
Helgasercle kicks ass. She uses the soul of a demon rival that annoyed her to put a barrier around the Mage Tower in the game. She’s a world boss in the Royal Territory of the game.