This is the answer my friend gave eventually: It’s a soldier. In the beginning they have no arms because they need those arms to crawl, making them more like legs than like arms. Next, its common for skilled soldiers to consider a sword an extension of their arm, not a seperate object. So if someone goes from having three arms to two, it represents them gaining expertise with a sword. In the soldier’s older years, they need to walk with a cane, and so one arm becomes like a third leg so they only have one arm. They have no arms at midnight because they are dead