From this point on, let's go into more detail.

What do Necromancers have to do with it? This topic seems to be about demons. Well, Chaos is okay, as it has a lot of good abilities besides spells. But without Darkness, a demon will definitely lose. Upgrading Light for a demon, in my opinion, is nonsense; what does it need it for? If you are so confident in its practical use, what spells are you going to use there?

Necromancers are relevant here because Light magic is also not useless for them (although you can argue that only Darkness and Summoning suit them – well, okay :D). Also, you keep making categorical statements everywhere, like "Light magic is nonsense for demons." Why would a demon take Darkness against a Necromancer? And yet you insist that a demon will lose without Darkness. As for spells from Light magic, for example, "Divine Power" is most suitable for demons.