Since bats may appear from different directions, simultaneously to one another and other monsters, they can get dangerous especially early game. The best weapon against bats is a regular sword swing (not a club or dagger), since its angle is large. Finding the right timing is easy for a single bat, but might be tricker for multiple fliers. One strategy is to move in a contrary direction to the bats so they are all on one side, and swing at them all at once.