“Detect Evil” usually means “Detect <what a paladin’s god would consider> Evil”. My assumption with any evil-detecting blade, in a setting where evil isn’t an objective phenomenon as material as electricity is in ours, is that it glows when whoever created it would, knowing everything there is to know about the target’s memories, consider it evil.
“Detect Evil” usually means “Detect <what a paladin’s god would consider> Evil”. My assumption with any evil-detecting blade, in a setting where evil isn’t an objective phenomenon as material as electricity is in ours, is that it glows when whoever created it would, knowing everything there is to know about the target’s memories, consider it evil.