Hellfire only deals damage too effectively – it doesn’t overkill creatures. A 1/1 creature will only be assigned 1 damage. This makes the card description wrong and (IMO) makes the card more powerful than it should be.
This is (of course) as intended. If you could overkill as you say, the card should cost far less. Paying 8 f to hit a 5/2 5 times and the other 1/1 4 times is abysmal value. The card is balanced at 10 damage as well, it got nerfed not because of its power in a vacuum, but because of the existence of Doomsday, which allowed an OTK with 2 copies of Hellfire.
The fact that you sometimes get blown out by this card is a sad fact of life. It IS an 8f cost card, after all. It SHOULD pack a punch.
With regards to the card text, I don’t see what in the wording points to the fact that it can overkill a unit. I agree that it doesn’t indicate the contrary either, but that does not mean the description is wrong per se. It’s just that sometimes effects are too wordy to be explained in complete detail (like how random distributions work).
Hellfire would be a really bad card if it could overkill. Then it could only deal 1 damage to a creature for 8 faeria, at worst.
It’s already pretty underpowered on average. It’s only worth it if almost all the damage hits the targets you wanted it to hit. 8 faeria is a large investment. Losing that much faeria on a card that didn’t help barely at all can cause a loss. It was better balanced at 10 damage, but that made it work too consistently in OTK decks.
If anything, they should maybe even drop the cost to 7F to make it a little better. 8F for 9 random damage is a litle underwelming.
Besides, you cannot overkill in Faeria. Drain life only deals 1 damage to targets with 1 hp. Makes sense.
