Player Killer says the great Mr
Though not ranked very high on the list of useful cards, its easy enough to use this to make it easier to summon some of the Frightfur which require more than two monsters
It's nastier in Type Four where you keep them from playing a big part of their hand to stop it since they can only cast one spell per turn and most answers are pinpoint removal like Utter End or mass removal like Wrath of God
However, his Special Summon, which returns 10 types of cards from the field and hand, has quite strict summoning conditions for any of his decks, so depending on the situation, it may be easier for Sopia to bring it out
Tribute 1 face-up monster with 2400 ATK or more or 1 face-up "Squire" or "Vassal" monster with 800 ATK and 1000 DEF you control, then target up to 3 cards your opponent controls
During the opponent's turn, if Diabellstar the Black Witch is sent from your hand or field you can throw away one other card from your hand or field to bring this baby back