Not all Cosmic Horrors were on a level where even Ultimate existences couldn't kill them and could only force them back beyond reality.
Raikis might have been unhinged, but he wasn't reckless enough to pit Rishia, someone Aleksas clearly favoured, against a Cosmic Horror that could kill her instantly.
"Calm down, Rishia. Think about it logically," Arthur said. "Whatever's behind that door is definitely powerful, but it's also definitely not something the two of us can't defeat, even if it's going to be a difficult fight."
"I know that," Rishia replied, "but fighting something whose existence constantly corrodes your mind is easier said than done."
She clenched her fists silently, purple scales briefly spreading over her arms, then took a deep breath and relaxed, the scales fading away.
"Using that runestone was the right choice. Cosmic Horrors that can die can only be killed with cosmic energy."
