First, a disclaimer: Satan's Blood is technically not a hot sauce. Technically, this ultra-hot concoction is properly classified as a food additive. Why? Because it is NOT intended to be used directly on ready-to-eat food but rather only as an ingredient added to recipes during the cooking or preparation process. Yes, Satan's Blood is that hot - in fact, it's #2 on the list of hottest hot sauces sold by the Carolina Sauce Company, measuring in at 800,000 Scoville units. In contrast, military-grade pepper spray rates "only" a mere 500,000 Scoville units.
Satan's Blood contains only 2 ingredients: Pure Capsaicin extract (the stuff that gives chile peppers their fire), and red wine vinegar. I'm guessing the latter is added primarily for the blood-red color it gives this product. And if you're looking for flavor with your fire, you won't get any here because Satan's Blood is PURELY about the heat - painfully, hellishly unforgiving and long-lasting heat. So what's the purpose of such an extreme ultra-hot? Two-fold: First, for the hot sauce collector or the person looking for a provocative conversation-starter to keep on their desk (or shelf or bookcase etc.), Satan's Blood is a must-have. It really does look like an old-fashioned vial of blood from the lab of a mad scientist. The second purpose may be less obvious: If you make your own hot sauces at home and are looking for capsaicin extract to add to your own recipe to bring it up to ultra-hot heat levels, then Satan's Blood is the sauce (or food additive) for you. I guess there's a third purpose, too: If you like making ridiculously hot chili or Buffalo wings or other such food, you can add Satan's Blood one micro-drop at a time to bring the heat level up as high as you'd like, WITHOUT altering the flavors of your recipe (remember, Satan's Blood adds only heat and has no flavoring ingredients).
So do I use Satan's Blood in my kitchen? Nope, and not because I'm a wimp, but rather because I make a living off my taste buds and can't risk burning them out. But I know veteran chileheads who do use Satan's Blood, albeit with the respect it warrants. And I also keep a bottle on display, because it looks really cool.