you got a point herePersonally, I'd love to see everything have strengths and weaknesses to different kinds of attacks, like you mentioned mindless robots vr psy type attacks. Fire elementals vr fire attacks, etc. Then again, I'd love to see us players get some resistance to our own power sets- are you a psyonisist, master of the mind? Then it makes sense you'd have some resistance to mental attacks.
yep it makes definitely sense, that there are immunities for certain powers (which the character has himself for example like you stated )
but then it also would be as logic to have weaknesses too - like a fire powered guy has weaknesses against one with ice or vice versa for example
Immunity or resistance to makes sense for many powers. You could also do an immunity to a power you don't have. Like Cyclops' force beams and his brother Havok's [quantum, I forget, did they decide his power was quantum?] energy beams. It has been shown that each is immune to his brother's power but can be affected by their own power if it is reflected back to them.
Now way back in the 60s, Johnny Storm Human Torch fought what he thought was the original Human Torch of the 40s, turned out that it was actually Toro and they both were able to do some damage to each other but their powers were somewhat resisted.
Or Superman, while not especially vulnerable to magic, is as affected by magic as a normal person. So he has absolutely no resistance versus magic attacks.
So every "plus" you take, you must take a "minus".
Now how you would program something like that and keep it working ....
Well, I believe brainstorming like we do can give ideas, even if it is absolutely unrealistic and maybe our idea makes them have other ideas, so I don´t really mind the question how it is to be programmed. It is just that one should not be too disappointed if unrealistic ideas won´t be used . Anyway, since it is absolutely chaotic having unrelated immunities, that is why I stayed with the logic aspects where I agreed with that idea but I won´t shed a tear if it won´t make it
About your question, they called it most times ambient cosmic energies (which he also did automatically and consciously absorb in various ways - as I see it he kind of must have been even able to absorb a Heralds Energy according to that logic, thinking about it), which mostly where converted into some kind of plasma beams.