Question:
Is line of sight from any part of one tile to any part of the target tile? If so, are there any partial cover mechanics?
Blue is really hard to read on darkling.
There is no partial cover, you either get the full bonus or you don't get any at all. I'm pretty much working on the rule that cover provides cover from a 90 degree cone. There was a bit of a debate going in my head about whether Shadow 7 was in cover from the topmost enemy, but I decided to rule in its favour(not that it needed the help to dodge the first shot). I will mostly be eyeballing cover.
How much of a resistance from magical energy per turn could we get if we manifested that right now?
You could get a reduction of 1 guaranteed, or 50% to block 2.
Could we give shadows the ability to give other shadows traits?
Sorta like Slivers do in Magic The Gathering?
Of course. The swarm may grow strong together. But remember the limits of your knowledge.
We know the portal requires energy to keep open, we can use logical thinking to conclude it would not be emitting light if it could not lose energy, as it is directly tied to our world which follows our laws, provided the energy is not dissipating instantly into the atmosphere (which we have no idea of knowing if it is or not), we can assume and logically attempt a mutation to absorb that energy, as it is just as foreign as the Shadows of Keb to the world and should not react poorly with the Shadows. Should the mutation not be successful, then we aren't trying the right spectrum as the portal clearly emits light.
I would think that we could use logical jumps to try to get mutations that may or may not work provided that we have a logical reasoning behind it.
Light is insufficient to generate noticeable amounts of power. It is quite enough for growing plants, but restructuring yourself is a different matter. Actually, conventional methods of energy generation are out mostly cause I don't want you to spend all your time basking in the sun or acting as a sentient windmill.
Logical jumps are allowed however, and you make a good point that the energy coming through the portal is foreign to this world, and familiar to you. You may manifest the ability to gather 1 energy from the portal. Draining more than 1 every second turn stops the inflow of Shadows though, and may damage the portal. (So you can alternate Gather and Manifest with exactly one Shadow)
Also, since you talked about energy transfer, it is possible to manifest the ability to transfer energy to and from another Shadow thanks to your knowledge. Melee ranged though, until you gain a better understanding of magic.
By the gods, I keep forgetting things.
PS: You may spend a turn examining something. Like for example Mage corpses, which 3 Shadows appear to be standing on at the moment.