MC's last desperate play paid off...mostly. Him resisting the empress trying to run Lumi's sword through him is raw as hell.
You know when the MC got his legs burned off, I knew someone had to come to the rescue unless the MC had the strength left to start mauling the empress with his teeth. Honestly, I didn't expect one of the three sisters out of all people to show up but it's a clever twist. Luckly for the MC, she didn't get a non-virgin collar when they mated. I assume that she technically has virgin blood to open the door unless the empress lost some of her powers during the struggle.