Seriously, though, Toriel's story with Frisk, short as it may be, is one of the most heart-wrenching in the game. Whether it's from sparing her and having to leave her behind in the Ruins, or from watching her fall to her knees and crumble to dust (yet still wishing well of you, in her own death throes). The lighting and color contrast is so powerful here. I see the background as flames, but whether it's Toriel's own flame powers, or it symbolizes an outside threat, Toriel still holds Frisk close.