Midnight is a male blackfur. While serving as a Patrol Guard before and after the Weasel War of 1149, Midnight also filled the role of Lockhaven's blacksmith. After becoming dissatisfied with the role of the Guard in the Mouse Territories, Midnight sought to overthrow the Guard and rule over all creatures with an army of followers. He united his army with the symbol of mouse protection: a powerful weapon known as the Black Axe.
Midnight had grown resentful of the Mouse Guard following the Weasel invasion for which Gwendolyn did not act on until the mice were forced into war. After the harvest of 1151, he came upon a hidden passage below the armory leading to a hidden library. He found a book that described the legend behind black axe
The outpost of Caolgero, which was resided and guarded by Conrad, served as an ideal place for Midnight to carry out some secret meetings with a merchant mouse plotting to overthrow the Mouse Guard. Conrad began to suspect that someone was inside his house, when he wasn't. The seafaring mouse hid himself in the eaves and spied on Midnight's meetings, but could not identify Midnight in the shadows.
One day, Conrad saw Midnight hand to the merchant mouse, a map and overheard the shadow mouse say "Lockhaven". Midnight made his way to Barkstone to relay final instructions to members of the Axe Army before he rallied members from Windshelm.
As Midnight carried a sack of swords, he met Saxon, Kenzie and Lieam as they were crossing a stream. He asked if they had seen the missing merchant. Lieam was about to reveal that the merchant turned out to be a traitor, but Kenzie cut him off and said that the merchant was killed by a serpent. Midnight took a sip of water from the stream waterfall then resumed his journey.
Later on that very night, Midnight assembled the Axe Army en route to Lockhaven, when Lieam showed up having been caught by two of his soldiers. He offered the redfur the choice to join his cause, but Lieam refused. Midnight had Lieam bound and taken hostage with his army.
By early morning, Midnight made his intentions clear to Lieam that he would wipe out every predator in the land and bring prosperity where the Mouse Guard could not and revealed how he learned of the Black Axe.
When the Axe Army reached Lockhaven, Midnight noticed that archers were waiting and became irritated that they lost the element of surprise. He ordered an all out assault. As archers exchanged fire, Midnight demanded to speak with Gwendolyn, threatening to kill Lieam. Rand refused and the battle went on.
Shortly, Midnight and a group of his finest guard managed to break through the front doors of Lockhaven. He noticed Meritt cutting the rusty chains that held the portcullis open and ordered the archers shoot him. However Meritt was able to cut the chains seconds before the fatal arrow killed him, causing the portcullis to block off the bulk of the Axe Army. Midnight noticed that Lieam had slipped away, but he proceeded to invade the city.
He led his squad straight to the Matriarch's office, but ordered four of them to guard the outside. He demanded that Gwendolyn surrender and described her Mouse Guard as inadequate and failing. Then Celenawe, Saxon and Kenzie showed up. At that point Rand recognized that Lockhaven's very own blacksmith had betrayed them. Gwendolyn declared him a traitor, but he managed to overwhelm her. Before he could deliver a killing blow with the Black Axe, Celanawe blocked it and fought him fiercely.
The oldfur struck Midnight in the side with a broken sword and retrieved his Black Axe. He was just about to kill the traitor with the axe, when Gwendoyln ordered him to stop. Celanawe could not stop the axe swing, but was able to pin Midnight against the wall. Midnight was defeated, his hands bound and was marched out of Lockhaven and beyond the scent border, never to be seen again.