You have to equip the dog collar (from the 50 affection chest in her room) and then start the fight with Hecate and the mantis girl.
The art isn't the best, but the character and scene designs are amazing and more than make up for it. This might be the first battle fuck game I've played that I feel gets the concept right. Sure, it's hard, but the difficulty adds to the overall experience of the setting and tone of the game. This was the developer's intention, and he seems frustrated and disappointed that players are complaining about the difficulty. I much prefer this to BF and RoL games where you have to intentionally lose to see the scenes. To compensate, you get an item to prevent Game Overs, and you can automatically refight bosses if you lose to them. The new 1.10 patch adds a "Spectator" difficulty that apparently has a joke ending.
I'm playing around with RPGMaker Trans and will put together a basic interface/gameplay patch so maybe this game is bearable for the Japanese impaired. Definitely looking forward to the future chapters, and hopefully the artists refines his work a bit more.