Tiny wings are very much capable of lifting heavy things, but they have to flap super quickly. Humming birds have really tiny wings compared to their size, but since they never glide, it’s not important. The bigger issue is the position of the wings.
Since the line between the center of mass and center of force (the wings) is not perfectly vertical, Pit would lean forward during flight. His body would be suspended under his wings. This means his body is blocking most of the wind generated by his wings. So he would have to exert even more force to stay flying. Plus, your arms would get super sore when all that force is pushing them forward.
It should also be noted that Put doesn’t have the musculature to support this level of force. His biceps are connected to his arms, not his wings, so he must have a separate set of muscles specifically for his wings. The only suitable anchor points are his ribs and spine, but in no art do we see the require muscle groups around his shoulder blades.
In short: I don’t think this is real, guys.
I thought about that, but I don’t think that makes sense in this situation. The wings and arms must use different muscle groups, and the biceps would be used for the arms, not the wings. Furthermore, since the wings are on the back of Pit, the muscles would either have to wrap around the rib cage or go through them, constricting the lungs.