Blocktales Section.

Call red: Calls for red alone.

Red's abilities: Solo Slash. (Like Duo Slash but without blue and weaker so like 1 or 2 DMG, can be boosted to deal more damage though.)

Undertale Section.

Split Soul (AKA The switch soul) Resprite: a crack in the middle of the soul with one side of the soul being red and the other side being blue. Splits in half, same mechanic as the OG.