honestly, she ate her brother because at that point of time she was starving after 10 days, the brother should have been dead because beezlebub could not have fed the baby meat. Thus the baby would either have died along with the parents or died of starvation earlier, while that is still fucked up, its understandable why she ate her brother, as he was already dead and she was being forced into that predictament, ( this chapter really reminds me of the book alive)

fight i really disliked, like i wished the author let him died to the church girl, like when she had the 5 mins thing on, as that would have made more sense, she would have studied everything about beezlebub during her time at the church and it would have made more sense for her to be able to defeat him easily.
Another thing i disliked was how beezlebub somehow became an angel and then suddenly lost because of the witch person doing some shit with the finger he had gotten in the earlier chapter. In regards to the angel bit, you would assume that God would have made a failsafe so no matter what a demon would not be able to injest a part of an archangel, even more so if that angel was a devil previously. Honestly i really disliked that whole arc, only thing i liked was how Golem was bad, but became good and when he died, it was really sad as he asked if he did a good job protecting femc,
What i also dont like is how they say the mc has gotten weak, like ya its unique as usually a mc gets stronger as they age, or at least become more wiser in their fights as a result of their experiences to make up for their lack of strength. But so far the mc does not do any of that, he just goes into everything head first. I wished it was explained why he was weak, also for a chosen child, he is weaker than what i expected as well, he is seemingly unable to defeat a devil on his own.