To everyone confused about the coward naming.
I believe it’s because mages are meant to take pride in their prowess and display it to all, welcoming equals to challenge.
Meanwhile like sith (lol) there are only ever two going around hiding their power and wiping out those weaker than them while making it look like they’re the weaker ones, which is cowardly.
If the demon king knew their true power he would send an equivalent force, but instead they’re chipping away at the foundations in secret.
That’s not to say it isn’t smart by our standards, just cowardly by the standards of mages.
Like someone who pretends to be bad at a game to beat someone who’s inexperienced by comparison. Just think about it and you’ll understand.