I mainly know them as Camel, as that's what they're tagged as an artist name on -booru type sites. I think it's taken from Camel cigarettes. At any rate, sorry if it caused confusion there.
Nana doesn't have a vore fetish, but I get the impression he does like ryona in general, with vore falling under that scope. I think that if you were to ask him which one was his favorite, or the one he put the most work into, it would be the chase sequence in the new stage where Youki and several shrunken goblins are being chased by a gargoyle girl. When I first mentioned to him the idea of having a giant gargoyle prey on the goblins, he seemed to be very fond of it and said he definitely wanted to implement that. The goblin girls have several sprite animations designed for this part. Nana mentioned the goblin girls have three different begging animations before they're mercilessly devoured by the gargoyle girl, and they'll be randomly swallowed or chewed up by her. He put a good amount of work into that part. The general premise of a cute and helpless girl being mercilessly preyed upon seems to be in his strike zone, whether it's the goblin girls or Youki. I think just the general idea, like, on the one hand you have what is a normal everyday occurrence for the predator that brings it pleasure and sustenance, and on the other you have this cruel and merciless end of the prey's life, this contrast that it's ordinary for the prey's life to be trampled upon so casually, that kind of ryona seems to be his kind of preference. Nana specified that his favorite enemy is the goblin girls because of the various misfortunes that he can subject them to.
More than that though, Nana's the type of person that wants to make people happy with his work, so I think that, as people became interested in it because of the vore, it was natural to start including more vore as a response to the increased interest in it, which feeds into itself. A retained interest in vore in his works will probably lead to him naturally making more vore content. I intend to continue helping Nana where I can with his future games (bug testing, discussing ideas, etc), and will naturally bring up ideas for vore wherever I can. It's probably a safe bet that if the premise will allow for it, there'll be more vore in his future works. An idea for another Youki game was discussed...but no promises on it getting made. Probably shouldn't say more on that subject.