That's exactly my point. If we try to turn ourselves into a monster using the trial of blood alone, what we're going to end up as is a really dangerous beast lacking any technical skill and knowing all of two spells that scares the hell out of people, but really isn't much of a threat to a hero.
I'm not saying that we should stop gaining power. I'm saying we should sell that pelt we've been carrying around or buy tools and work it into something. I'm saying we should learn how to actually use a sword, instead of leaving it as that sharp chunk of metal at our side we mainly use to find the hearts of things after we kill them with magic. I'm saying we should learn more spells than basic fire attack and basic ice attack.
I'm saying that we shouldn't try to turn ourselves into a monster using the trial of blood, but should instead make a workable base with it and gain strength through other means from there. And we've already got a workable base. With our regeneration alone, we should be able to push ourselves far harder than a normal person. With our enhanced senses, we should be able to actually track down the hero we must kill. With our wind affinity, we should be able to pull far more out of any wind spells we learn than a normal person (once we actually learn some, anyways). Let's take that base and turn it into something actually dangerous.