I think everyone basically just creates a tiny "Hitbox" at a point on the weapon or character to check if the hitbox collides with the enemy.
From there, you can just assign events to deal the damage.
Yes you could do that or make the sword a separate sprite and give it the Pin ability, then have it rigged to on button clicked, mouse down or whatever you want to use to tell your character to strike, the sword sets it's angle to one angle (Middle of swing) then quickly switches to the next one (end point of swing) then resets to original angle. The gaps in between each position would be small enough that the target would still get hit.
Casus Belli: A reason or cause for war