It's between the first and the last for me, depending on what story you want to tell.
The first one has his sword out, and their pose is more dramatic. The male is clearly the protector, here. That's your classical He-Man pose, very successful genre.
The last one has a similar degree of drama, but it's more subdued, and I like it. She's holding the shield, and he has his sword ready, and they look sad like they're special lovers and want nothing more than their place in this world, but they're going to face the monsters together.
The rest are boring AF.