Lore-wise, what exactly is Mana? All I know is we use it, there are some leylines, and Arcane magic is drawn from it. Which also makes me wonder, if Arcane is drawn from Mana, where does Fel come from? I know they are polar opposites, but is there some substance Fel originates from as well? Is Mana and whatever Fel is potentially from just leftover life energy from when the Void and Light clashed?
Please help.
I didn't find the right solution from the Internet.
References: https://us.battle.net/forums/en/wow/topic/20759596847

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