Basically, in similar worlds, heroes either fight the Demon King alone or in small teams, for reasons that are quite simple.
Human forces and firepower are insufficient.
Generally speaking, the Demon Clan possesses ample troops and powerful firepower, or can command Demon Beasts to fight for them. In comparison, the forces humans can mobilize are much fewer. Especially in this era, there are no large-scale destructive weapons, nor are there easy-to-use weaponry. On a purely number-based battlefield, the side with the most numbers and least fear of sacrifice naturally holds the advantage.
Thus, to counteract this advantage, the best approach is to concentrate small elite forces for decapitation operations against the enemy.
Whether it's against the Demon Clan, the Insect Race, Green Skins, or anything else, this tactic is somewhat effective.
The premise is that the hero must be strong enough.
