The instant the monster appears from beneath the darkness, Mayumi appears behind and above it, stabbing her blade downward into its back. As the blade nears the creature, it seems to grow, drinking in the beast's reiatsu.
It shouldn't grow this fast! Mayumi thought to herself. It grows through ambient reiryoku, but to grow this much, this creature must have monstrous amounts of reiryoku! What on earth am I fighting?
As she stabbed downwards, she hoped to plant the blade in the roof beneath them, thereby rooting the monster down. Of course, it could tear itself through the blade, which would work just as well for Mayumi.
"You won't be speaking to anyone, monster. I'm stopping you, here and now!