Metal Birds?

Clint's fist hit the wall with surprising strength, considering he had spent the last few days fighting robots. He instantly regretted the decision and crumbled down to his knees, forehead hitting the wall. He cradled his hand and mentally punched himself in the face. His muscles ached and the cuts on his arms stung and his eyes hurt and his heart was heavy. You might be wondering why all of this pain was happening to our poor main character.

Well, Clint Barton saw his responsibility die right in front of his very own eyes.