The Truenamer manual gives the following interesting advice:
Open the book of hideous darkness and read the rules for the victims. Then remember how good Truenamer is at putting their knowledge checks to stupid levels. Between the INT focus, the fact that you probably only need knowledge skills, the Knowledge Focus feature, Universal Aptitude, and Hidden Truth, you can get a frighteningly high K: Religion check (this is used on victims), of course, from level 3 or so. Consider a perfectly reasonable illuminal truenamer with 16 INT and the Naen seal. , , For almost no investment you get 6 (ranks) + 3 (INT) + 3 (knowledge focus) + 2 (Naen) + 5 (universal talent) + 10 (hidden truth) = +29 before you even roll the dice. If you've added all the trivia listed on page 5. 27 of the BoVD you will almost certainly reach the highest level of rewards. And that is at the level 3The only real investment made is in K: religion (does not hurt) and the insertion of your knowledge focus on religion (which in turn is not a big loss). Even if you do not add all the traps, you're just letting a living being kill you everyday (but probably unconscious), long enough to whip out your dagger and recite your vile master's name a few times, and you will guaranteed to roll high enough to get a free Planar Ally. How cute is that? Sure, you have to be wickedly repentant and your GM has to join, but all the rules are right.
Suppose that we have a DM that follows the rules of sacrifice RAW and that the truenamer is as described above (ie at low level and rates those exams +29 without trying) and the above listed foul victim once per Day for you party at a low level. How much benefit will the party have? For simplicity's sake, suppose they are sacrificing something commonplace in a wicked campaign, such as a lower man.
For reference, I have uploaded a screenshot of the two relevant tables here. Of special interest, I can not help but notice that many of these benefits are treated as if they came from a Level 20 caster. Could this be groundbreaking?