I noticed some comments asking what Crimson in Sheath does, so here you go.

I decided to use Agent Ransack to try and answer the question. It gives an effect called `Yujin_QuirkEvo`, which has a sub type called `Yujin_QuirkA`

From what it looks like, in the files, there are three quirks; `Yujin_Quirk1`, `Yujin_Quirk3`, and `Yujin_Quirk5` all has `Yujin_QuirkA` in their 'tag' field which have 'quirk evolutions'.
These are Yujin's default perks.

1, 3 and 5 appear to be replaced by quirks 2, 4 and 6 with whatever Crimson in Sheath gives.

Quirk 1 is an Eye Of Death / Eneveration-style thing; 15 accuracy, 4 speed, -3 speed, -10 accuracy. Quirk 2 is the evolution of Quirk 1, removing the downsides of Quirk 1.

Quirk 3 has buffs to Yujin's high roll and low roll to her damage range, but then is reduced by quirks that subtract from her high and low roll; Quirk 4 removes these subtractions, ergo, Yujin's minimum damage and maximum damage are raised significantly.

Quirk 5 effects has something called `Yujin_HealthL35F`, which is a combat stat multiplier regarding max HP, the `amount` written as "-0.35".
The evolution is Quirk 6 when you have Crimson In Sheath equipped, removing this downside and thus Yujin has more HP.

This is what Crimson In Sheath actually does.