Can you recommend a technique to beat lady butterfly? I've looked at the top YouTube videos but for some reason my boss doesn't react that way (the close step dodge then hit doesn't work because she block or runs and slices me).
I didn't watch any videos prior to fighting her. I was pretty defensive throughout, usually hitting her once or twice when she missed one of her attacks. If she misses she's vulnerable so that's your chance to do some damage. When she's in her second phase and starts the illusions, I just ran around (not fighting her at all) until they went away. When they turn into butterflies I used the umbrella prosthetic to defend myself. After that, I did the same thing as in phase 1. Stayed defensive and only hit her when she missed an attack.
I did have like 7 Gourd Seeds at my disposal and had quite a bit of health because I explored a lot of side locations before fighting her.