Shadrack exposes us to the horrors of war. He returns from World War I profoundly impacted by what he's seen and experienced. His neighbors are scared of him at first, but they get used to his strange ways. Despite the fact that he exists at the margins of society, both literally and metaphorically, we get the sense that he sees far more than people give him credit for.
In one touching scene, Shadrack recalls the day a young Sula came to his house – his first and only visitor. She was concerned that Shadrack saw the accident with Chicken, but he thought she needed some other type of reassurance – and it seems like he was right. All he said to her was "Always." When we hear this story from Sula's point of view, we don't know what this means. But when Shadrack tells it, we learn that he is trying "to convince her, assure her, of permanency" (1941.12). This sounds precisely like something a little girl lost in the hustle and bustle of a chaotic household needs to hear. Somehow, Shadrack knows that what Sula needs is confirmation that she can count on something. Maybe Shadrack is not as crazy as we think; maybe he serves as yet another reminder that things are not always as they appear.
At the novel's conclusion, it is Shadrack who leads the people of the Bottom to their deaths in the tunnel. As he stands back and watches the tunnel collapse, he seems to be one of the most rational characters on the scene. It's not that he's planned this or that it's his fault, but he manages to survive the one National Suicide Day that actually turns into a day of death. What to make of this? We don't exactly know, but perhaps Shadrack, despite appearances, is actually the most astute and observant person in town – the novel's voice of reason.