Morpurgo's Author's Note introduces us to Nicholls as though he's a historical figure who painted a picture of a forgotten war hero: Joey the horse. Note to Shmoopers: this is majorly made up. Sure, he might be fictional, but Nicholls still feels real. He's the ideal dramatic soldier: brave and unflinching, yet sensitive to the horror and death that surround him.
He's also Joey's first friend at war, although Joey sees Nicholls more as a colleague than a companion. But that doesn't stop Nicholls from showering praise on Joey and convincing Perkins, Joey's trainer, to be kind to him.
Poor Captain Nicholls is fated to death by irony. At one point he says, "This horse [Joey] is going to carry me through the way and, with any luck, out the other side of it" (5.11). Sadly, luck isn't on his side. In the chapter after we meet him, Joey carries him into the battle and emerges from the other side, riderless. But Morpurgo gives Nicholls the honor and respect he deserves, which inspires us to honor the real-life heroes of war, both human and otherwise.