Uneven wear on brake pad

It is not unusual to see brake pads worn like this.

The brake arms are not completely rigid, and when brakes are applied, the force of rim pushing the pads forward twists the entire brake so that the rear end of the pad is pushed into rim and front end away. When the brake wears so that it is flat against the rim, it will get this asymmetrical shape. When the brake is released, the brake arm returns to its original shape, and the pads become slightly toed in. If the pads are adjusted to be parallel to rim when released, the cycle starts again.

There are asymmetrical brake pads where most of the braking surface is behind the brake post. These might help with uneven wear and grabbiness, because the the change in geometry reduces the force the rear end of brake pad is pushed into rim.

It is not unusual to see brake pads worn like this.

In order to keep brakes from squealing pads are often set so that they hit the rim at an angle.

This means that the brake pad will wear at an angle.

That being said - it does look like someone was a little over enthusiastic on the angle of your pads.

The arrow indicated the direction of wheel spin.
The brake pads are pictured at an extreme angle to make illustrate the point.
Pads should be "toed in" just enough to stop the noise and no more.