Infernal Blood Magic, much like currently accepted Blood Magic, is wildly outdated (being 4 years old without proper updates for a while), and in my humble opinion, just as dogshit as BM. Mind you, the lore explanation was to make the redline itself be less BM-targetted and more towards enchantment in general, not my fault that Ensorcell is the mainstream enchantment bc its piss easy to make and costs literally nothing (average t5 blood mage pumping out 5 sreqs in a week). Maleus is corruptive, that is maleus' approved lore (which is why it does not interact well with souls, see: permanent loss of magic slots in order to even store it), and while yes, the marriage piece exists, the key part about infernal Blood Magic is not Maleus - it's rakir. While, yes, Maleus and Naztherak are required to perform a majority of if not all of the Infernal Blood Rites, what matters most and more is the rakir itself. Not only that, the maleus requirements on Infernal BM are pathetic (the highest one I found was 10), which - and you may call this a stretch, frankly I don't care - implies that Maleus in any higher quantity would make it too volatile, because Maleus is inherently corruptive.
The issue is that currently accepted MA Seer abilities seem to have redlines, abilities and lore that just let them supersede currently approved lore of what they interfere with/change/alter/etc. Which is fine. That's the cool factor about Seer. However, I'm sorry to both of you, but having to bleed on something doesn't make it cooler or more esoteric, it just makes it edgy and 'heh... watashi wa have blood book...' I can understand the aesthetic appeal, but its not as cool as people are making it out to be.
Finally, a note to any further comments made on this amendment: Please god read what unwillingly said. The Grimoire is written and balanced in a way that it is the only way someone can confidently out a Naztherak as a Naztherak without going through the shoots and hoops of learning through valid rp that tattoos = brands or something like that. This is a balancing change. As it stands, Naztherak are the easiest MA to hide. Case and point, I made it from T1 to T5 Naztherak, being active most if not every day of that tenure, until my crowning, without being outed. I outed myself when I made the 'Salatiel' angel gig. Up until then, had it not been for my own son talking shit, people genuinely wouldn't have known. Grimoires already have protective redlines, or the lack thereof (like how they don't have to look infernal in nature), and letting you hide its true nature on top of that is just excessive.