Bro, at least you got two girls coming at you without much effort. Enjoy it while you can (and you probably will enjoy it until the end of your lifetime).
Finally we meet the sister Lucoa did "that" with and seemingly turned her to the side of sisterly incest. Two super-busty goddesses sisters, what's not to like.
Never been a fan of the shota parts, I feel like the author has many maaaany more works with that so it doesn't need to be explored even more here, I was worried when the sword turned out to be another shota too but well, it is what it is.
So it was the sister, from that one chapter. Was kinda hoping she would be Lacuo's "love" child with her sister. That would have been even hottermore awkward...yeah, awkward.