To be honest, when these things come up, it is up to you to figure out a way this may be possible.
What tends to happen sometimes is blizzard introduces new lore, so originally it was thought htat light and void users couldn’t touch, but advancements, new discoveries, new individuals that achieved the previously impossible came about and made it possible.
You don’t alwyas have to know how, but usually you can come up with some sort of explanation that fits the criteria and lore information without validating it.
ofc you don’t know for certain if this is the ofifcial position or not, but hten most of the time you don’t need to know, different groups can have different udnerstandings of how things work, that they work is proof enough.
These aren’t necessarily ret-cons… . ofte n enough previous information is based on one in-game character or races’ knowledge or understanding, which isn’t always fully accurate or knows everything. Take the maps for example, ancient maps have many mistakes in it, in warcraft Bran charted the thigns and places he saw, these form the maps for the humans and orcs of the horde and alliance. These would not be the maps say the high elves have or the night elves or the dragons, but in time, new info will come, they’d meet other types of humans, dwarves, trolls that update that previous info.
It’s like the night elves and arcane magic, the lore never said they hated it, but punishing it by death made players think so. The lore showed the night elves knew arcane magic usage draws demons from the twisting nether to Azeroth and they are able to enter through the tears the usage makes.
For a while many players thought becuase of htis arcane was wrong or evil, and the night elves hated it because it was evil, but chronciles and later lore showed this was not the case, it was never evil, just volatile, night elves didn’t hate it, just had to stop using it because they knew it drew demons - the lore books actually show this, however what later lore shows, is that the night elves didn’t know you coud use arcane magic without a source like the well or ley lines, because they didn’t realise the imploded well had scattered a lot of its energy into the atmosphere of the planet - and it makes sense that a society that stopped using arcane magic, woudln’t discover that it was let loose into the world in the very air.
when the high elves break away, they discover this, but also when we discover other ngiht elf communities survived apart form the ones we meet in WC3, and they denver stopped using hte arcae, we realise they must have known.
The night elvews were also wrong that you couldn’t hide or mask the effects. We don’t know this straightaway when WC3 is released, so some of us conclude arcane magic is bad, and night elves don’t use it becasue bad is also evil and they hate it - but all the lore shows is htat they didn’t use it because they didn’t want demons through - not that they hate it, we projected bad in the sense that it is not good to use somethign that will bring an invasion to = bad as in evil.
The revelation and explanation comes later, when they show us that the high elves built ways to hide their arcane usage fromt he twisting nether, and prevent breaches from the twisting nether into our world due to their arcane magic. Turns out the humans however did not heed their teachers’ warnings, cos is is their meddlign outside supervision that allows the first demons to start coming through again.
Long and short, finally when chronicles hits, it is definitevely stated that arcane is order of magic, now this is hinted at and mentioned obscurely with the titans in other texts, texts most people don’t read or are ware of, but most have seen the conversations in Wc3, and the short wowpedia explanations, and rely on those far too heavily until someone updates the original narrative with the corrected information. Sadly there sources is greatly olutdated articlaes and they fail to factor in new lore.
Take your void question. Did you read the short book released on Alleria? How though talented with the void, she is still a being of light, like the Locus Walker and has access to the light, like every being, but like most classes - rogue/warrior/mage/hunter/DH etc - having access doesn’t mean they use it or master it like a priest or paladin does.
What does this tell you about the void?