Where everyone is dead on both teams? Yeah, that happens sometimes, usually from a reflect damage

In this case, my guess is your Scyl put a brimstone on someone, that champ killed your last teammember with an active skill, which triggered brimstone, which killed anyone left on their team

it's rare for her to get that blessing to work, normaly it takes almost 10 turns for her to get one on a enemy, and for more context, she is my pve champ, I don't alot of pvp champs, only using what i have until i get the right champs