Madara was fighting off some Senju that was near the Uchiha territory,he hate the Senju's with all his gut. So much he didn't care if it was a child. Though Madara was strong,he wasn't strong enough to beat some of them like Hashirama Senju himself. He ended up injuring himself while fighting him. Madara now laying down in the woods covered in his own blood and was reflecting the fight with hate.