Todays COTD of the day is Subterror Fiendess, a level 1 spellcaster for the, currently, TCG exclusive Subterror archetype. By sending her from your hand or field to the grave and targetting another Subterror monster you control, she can negate a card or effect activated by the opponent and then flip that monster face down. Her second effect can flip a monster you have face down and then special summon any Subterror from the hand or grave.

Her first effect is great for the archetype, allowing her to act as a pseudo-handtrap aswell as allowing her to trigger the in-hand effects of the Subterror Behemoths. Her second effect, allowing her to be a one-sided book of moon.

I like this card for Subterrors, it might just be the final piece that makes them playable. They gain a themed negation card with no cost aside from needing a face-up Subterror. The only downsides are the attack and defence points and her second effect needs a Subterror in hand or grave to activate and resolve, but otherwise she's a solid card for an otherwise weak archetype.

4/5 for Subterrors, 2/5 splashed into other decks.