That's exactly what I mean by cohesion. If it's a series, there has to be something that makes it a series. If you want help coming up with Aether and Entropy, it would be nice to know what you're ideas for them are. Having said that, here is my idea for the Entropy "technology":
Radiation Therapy (permanent)- At the end of your turn, Radiation Therapy turns a random enemy creature into an Abomination.
Upgraded:
Radiation Therapy - At the end of your turn, Radiation Therapy turns a random enemy creature into a Micro Abomination.