Since the item's theme is demonic LC, all the rivaly lines towards demons are unused while it is equipped. Except for 1. It probably was just an oversight.

Legcom_rival_13 is a line specifically against demons (hooked up to killing Doom/SF/SD/TB). So Legcom_dem_rival_13 should be removed from the response rules because it goes against the theme. dem_rival_12 and dem_rival_17 are already removed.

rival_12 is "go back to your hells."
rival_13 is "begone hellspawn!"
rival_17 is "your terror has ended."