The card of the week is Blood Pet, a ritual on a stick. Rituals are a one time effect that will add mana to your mana pool. This can help you get your commander out early. Or you can have an explosive early turn that your opponents just won’t be able to catch-up to.
Blood Pet has several advantages going for it including its creature type and it can be activated at instant speed. Being a creature allows you to store mana into Blood Pet on one turn and redeem it on another. In addition Black has a number of ways of recurring creatures. In addition having an activated ability that gets around summoning sickness and can be done at instant speed makes this very flexible. You can cast it, and immediately sacrifice it to get a death or sacrifice trigger.
As both a ritual and a creature it is rather unimpressive. Creatures are not only the easiest permanent type to deal with its stat line of 1/1 means it won’t be surviving combat. As a ritual you only get back the mana that you put in.
The downsides of this Thrull are outweighed by its Advantages, and ultimately its flexibility.
Blood Pet is most effective in Aristocrat themed decks including; Tessa Karlov; Meren of Clan Nel Toth; Korvold, Fae-Cursed King or Mazirek, Kraul Deth Priest. As well as being an an effective ritual in any deck that runs Black.