@killari3211 I don't think it will be a tale with a true dark ending, for one simple and admittedly silly sounding reason: the interaction with the cat. The inclusion of those silly moments is showing to me that the mangaka doesn`t go full corruption of paradise story. Like you said, I think they will definitely dive deeper into that direction. Already in the pilot the Kemo wanted to execute him, so the tone range was from the beginning pretty grim. But as they include a lot of silly side stuff, I can`t imagine that they will destroy it all.
But let`s see, this is definitely one of the best mangas I am currently reading. And honestly, if the mangaka indeed releases the full darkness and corrupting influence of humanity, my respect to them for pulling through. Too many stories go "And the power of friendship saved everyone" (which can be really great, but only if done right).