Boundary of Memes.
Instant sub.

I chose 400 max HP for two reasons:
1. Balance purposes, so you can't deal super high damage from the get go while staying safe.
2. And tension, as from the very start you'd be considering wether you want heal, use Sacrifice or maybe do neither, thus creating a playstyle that I don't think any base character has.

Also, one thing to note. Sacrifice doesn't go through shields, you may be able to use that :)

While the mod is great, have you considered giving Calli more HP to work with? Not only does she start each run missing 100 HP, but she only has 400 max HP to boot (meaning she only has 300 HP at the start of any given run). I don't actually have any problem with Calli starting her runs damaged, I think that was a great touch to allow her weapon to deal damage right away, but because her HP is so low I always just end up discarding her Sacrifice spell right away every run, and most bosses are nearly impossible for me, even when they're merely World 1 bosses, because she can't take hits pretty much at all. If I had to suggest, maybe give her 900 max HP, and start her at 800 HP every run, or at least 700 max HP and start at 600 each run?

Love the Hololive Mods bro, keep at it!

Have you installed MoaLuaPower? Because the mod requires it to work

I might just be dumb, but how do I get the souls mechanic to work? It seems like I'm just not collecting any

astolfo bean and mori. yes