Governor-General Nagumo was described as possessing a slight build and heavy oriental features. He wore a mustache and his hair was turning silver. He ruled over Verthandi on behalf of Duke Hassid Ricol.
Shortly before the arrival of the Gray Death Legion on Verthandi in 3025, Nagumo was approached by Olav Haraldssen from the planet's Council of Academicians. Haraldssen proposed extending an offer of amnesty to the rebels resisting the Kuritan garrison forces as a way to end the ongoing raids and attacks. Nagumo reacted violently to the very idea of showing mercy towards the rebels.
|“|| The penalty for resisting the Draconis Combine is extermination! Do you hear me?
-Nagumo cows Olav Haraldssen.
Governor Nagumo directed Colonel Valdis Kevlavic to take a force and investigate the purported supplies DropShip that was approaching Verthandi. After being alerted from the Kuritan base on Verthandi's moon that the DropShip was in fact carrying a group of mercenaries, Nagumo ordered a patrol of aerospace fighters to attack the inbound spacecraft.
When a Kuritan DropShip recovered Gray Death fighter pilot Sue Ellen Klein from her drifting Chippewa in the aftermath of the orbital battle, Nagumo embarked on a campaign to win the young woman's confidence. He wanted to glean any useful information on her comrades from her. This plan would later have grave consequences for Masayoshi Nagumo.
|“|| You fought bravely but - for some reason - your comrades abandoned you.
-Nagumo's manipulation of Sue Ellen Klein begins.
A warehouse fire in the city of Regis a few weeks later was discovered to have been set by Verthandian rebels. The surviving rebel, under interrogation, revealed James Thorvald's plan to attack the University of Regis using the cover of darkness and the fire to mask his force's infrared signature from orbiting surveillance satellites. Governor Nagumo decided to allow these "Free Verthandi Rangers" to get close in to the University and walk into a massive ambush.
While the ambush did kill a number of rebels - James Thorvald amongst them - the unexpected intervention of Grayson Death Carlyle and his MechWarriors made the action a costly one for Nagumo's forces. Facing an imminent visit from Hassid Ricol to inspect the situation on Verthandi, Nagumo ordered Colonel Kevlavic to find and destroy the remaining rebels.
Massacre at Fox Island
Nagumo's cultivation of Sue Ellen Klein paid off when she offhandedly mentioned Gunnar Ericksson to the DCMS fighter pilot Nagumo had planted as her sexual partner. Throwing Sue Ellen into the dungeons underneath the University for the time being, Nagumo identified Fox Island as the rebel headquarters. He dispatched a DEST commando team and a number of BattleMechs to raid the Fox Island base and then set a trap for the rebel ’Mechs and infantry, which were away on a raiding mission.
Forewarned by the fatally wounded Jaleg Yorulis, Grayson Carlyle and the rebels did not walk into Nagumo's planned ambush. Colonel Kevlavic and his command lance caught up with the tail end of the rebel convoy and engaged Carlyle and a pair of Verthandian trainee MechWarriors, but were unable to stop the rebels' escape. Governor Nagumo was extremely displeased by Kevlavic's performance.
Used and Abused
After the Gray Death sent a coded transmission to their JumpShip - the latest in an escalating series of rebel actions - Nagumo found his control over Verthandi slipping away. He turned to the interrogators who had been working on the captive Carlotta Helgameyer, and from her learned that there were numerous rebel sympathizers inside the puppet civilian administration. Armed with a list of names from Helgameyer, Governor Nagumo arrested 117 Verthandian officials and had them all executed in the University courtyard; Olav Haraldssen was the first to die.
Facing the Red Duke
When Hassid Ricol arrived on Verthandi, Nagumo had to explain his actions. He was surprised to learn that Ricol had encountered Grayson Carlyle before, but was unable to concede that Grayson's unorthodox infantry tactics could be so effective against BattleMechs.
|“|| BattleMechs rule the battlefield and always have! It is unthinkable that foot soldiers could bring them down!
-Nagumo's rejection of Carlyle's anti-'Mech techniques.
Capturing Lori Kalmar
As the situation deteriorated on Verthandi, Governor Nagumo finally hit on the idea of luring the rebels out instead of merely reacting to them. The rebels had been acquiring supplies and munitions by raiding the storage dumps set up by Nagumo's own troops.
He had a new supply base set up to tempt Carlyle and the rebels. While Carlyle and the bulk of his raiding force managed to escape the ambushing Kuritan 'Mechs, Lori Kalmar was forced to eject from her damaged Locust and she was taken captive.
Beginning of the End
The prospect of Lori Kalmar being subjected to torture at Regis University spurred Grayson Carlyle to mount a rescue mission. His commando team included Sue Ellen Klein, who had been rescued by the rebels from a Kuritan slave column. They effected an entrance into the University with demolition charges, which alerted Nagumo and his guards.
With fire spreading out of control through the University complex, Nagumo prepared to evacuate. He was intercepted by a vengeful Sue Ellen Klein, who was armed with a sonic stunner and a sharp combat knife. He tried to shoot her, but she immobilized him with the sonic weapon before tying him to a chair. Nagumo was unable to move, but he was fully aware of what she was doing to him.
Death and Legacy
It is implied that Masayoshi Nagumo died at Sue Ellen's hands, although no traces of him were to be found after the central tower of Regis University collapsed. Command of the Kuritan forces remaining on Verthandi devolved to the ineffectual Fleet Admiral Isoru Kodo.
- Mercenary's Star, pp. 29, Governor Nagumo's appearance
- Mercenary's Star, pp. 29-32, "Nagumo rejects the amnesty initiative"
- Mercenary's Star, p. 31
- Mercenary's Star, pp. 33-34, "Nagumo orders Kevlavic to intercept the incoming vessel"
- Mercenary's Star, pp. 48-49, "The Gray Death's true identity is exposed"
- Mercenary's Star, pp. 127-132, "Nagumo welcomes Sue Ellen to Verthandi"
- Mercenary's Star, p. 127
- Mercenary's Star, pp. 148-151, "Thorvald's plans are discovered"
- Mercenary's Star, pp. 173-176, "Nagumo's directives to Kevlavic"
- Mercenary's Star, pp. 196, "Sue Ellen reveals Ericksson's name"
- Mercenary's Star, pp. 223-227, "Nagumo and Kevlavic review the botched ambush operation"
- Mercenary's Star, pp. 244-246, "Carlotta Helgameyer's inside help at Regis University"
- Mercenary's Star, pp. 251-253, "Nagumo does away with Verthandi's civilian government"
- Mercenary's Star, pp. 277-280, "Nagumo's audience with Duke Hassid Ricol"
- Mercenary's Star, p. 280
- Mercenary's Star, pp. 296-297, "Nagumo plans to capture Grayson Carlyle"
- Mercenary's Star, pp. 298-300, "Nagumo's trap is laid"
- Mercenary's Star, pp. 306-308, "Grayson loses Lori to the Kuritans"
- Mercenary's Star, pp. 317-318, "Carlyle's explosive entry"
- Mercenary's Star, pp. 341-343, "Sue Ellen confronts Nagumo"
- Mercenary's Star, pp. 361, "Kodo assumes military command"
- Mercenary's Star (Novel)