About triangle adept

When a Raventome user has Triangle Adept, they receive less damage from Archers.... or at least it seems that way.

"Gives Atk+20% if weapon-triangle advantage, Atk-20% if disadvantage."

I think the 20% disadvantage also applies to the enemies, probably why Robin seems to take a maximum of 1 damage against enemies with bows.

So I think I understand your question, you're asking about the main value of those tomes right?

If so the big benefit of raven tomes is that it gives weapon triangle advantage against both the normal color AND colorless units. Combine that with Triangle adept to increase that advantage and your unit becomes a monster for facing down everyone of the color they normally have advantage against, plus archers, healers, and dagger users.

Yes, the effect will potencializes. 50% +20% on colorless enemies