So I hear Ougi skills from the Nyankoron can't be extracted once assigned to a weapon. But what about Ougi Spirit Blast from your starter weapon the Oni's Dagger? Once you get the Ougi to Level 30, can you use Momotarou to extract it then put it on some stronger sword? I think I've seen someone do it before... Mind confirming it for me?

Oni's Dagger doesn't even have an Ougi, it's called Oni Spirit Blast and it's a normal skill...
(The Ougi from Nyankoporon is called Ougi True Spirit Blast)...

But yeah, u can extract it even without maximizing it, juz Lvl the skill to 20 would be enough to extract it...
(The skill card can only be applied to Sword only, no other weapons)...

oni spirit blast can be extracted, but it is not a good idea as it consumes a whole lot of durability.