So, it's been pointed out to me that Mastering Black Scratch will either lower its cost to like 2, but not raise it's damage, OR raise its armour damage by a lot.
This is actually incorrect, there was apparently a misunderstanding between Alectai and I (probably my fault, honestly). What happens when you up Black Scratch is one of three things:
1. Cost goes down a fair bit.
2. Damage (but
not anti-armour) goes up a fair bit. More anti-armour on something spammable that also does solid damage is way too good. Not happening.
3. Cost goes down a little, damage goes up a little.
Where the confusion might have been is that, in the case of options #3 and especially #2, but
not #1, it serves as an excellent Anti-
Knightly Armour tool due to smashing through Rebuke pretty well (especially combined with being anti-armour)...if you Master it. Which is a big hole in your kit right now, an actual ability to make regular attacks against anyone with Rebuke 11+ (GKB goes through, and Sweeping Slash can very expensively and with a lot of waste, but that's about it.. a few more technically do with Severance, but only up to 12, 13+ is still a problem).
Now, anti-Knight stuff not being the priority right now makes sense, potentially, and the new plan is valid, but what you need at some point decently soon actually is Mastered Black Scratch for use as a way to fight other Knights if that comes up...which it probably will at some point, if not very commonly.
That's the intended advice from Reinald: Up Black Scratch to Mastered in a way that keeps its costs decently high for breaking through Knightly Armour, and get something else cheap and spammable. What order you do these in is a somewhat different question.