Eternum is a very good game, and during its development, I learned some things from it. As for the Easter egg about 'Eternum' in the game, it's just a minor Easter egg that was added with caribdis' consent. There's no real connection between us.
Regarding your question, I once asked caribdis a question about video format conversion, and apart from that, we didn't have any intersection in game development. However, after the production of version 0.2, Mayfly was fortunate to be played by Hexatail, the author of Agent17, and we had private discussions and exchanged opinions. At this point, Hexatail is the only author who, as a fellow peer, provided guidance in the game's production. I am very grateful to him.
Furthermore, I've noticed that there has been a lot of debate surrounding this Easter egg. I don't want uninformed players to suspect that I'm leveraging the popularity of Eternum. Also, for the sake of the game's independent identity... I will be removing these Easter eggs in the reset version and replacing them with some game-related Easter eggs that I'm more familiar with (if their authors agree).
Thank you for your love and support for the game.