Lady Butterfly? She’s technically an optional boss and really meant to be fought a bit later. She’s an absolute pushover once you have some upgrades and actually know what you are doing, but if you are just starting the game she is way too difficult. It’s honestly kinda stupid that you are allowed to access her so early.

The actual first boss is Gyoubu, the guy with the horse. While also difficult for first timers, he’s much more doable than Lady Butterfly.