Mokushu is a kingdom located to the south of Izumo that is known for its highly-skilled ninjas. Mokushu usually prefers to remain neutral in other nations' conflicts, but its most recent daimyo, Kotaro, harbors ambitions of expanding the country into a formidable power. At some point, Mokushu invaded the neighboring country of Kohga, razing its towns and then annexing it.
Mokushu has a vast array of terrain such as forests and intricate cave systems. In most of these locations, they are riddled with bamboo and caltrop traps.
In the midst of open war between Nohr and Hoshido, Kotaro recognized an opportunity for Mokushu to profit. Even though Mokushu and Nohr were usually at odds, he secretly forged an alliance with King Garon. In return for promises of gaining a large portion of Hoshidan territory once Nohr had won, Mokushujin ninjas ambushed and imprisoned any Hoshidans who ventured into their forests; Kagero, one of the most skilled Hoshido ninjas and Prince Ryoma's retainer, was one such victim.
When Corrin's party traveled through Mokushu in search of Takumi and Ryoma, they assumed themselves safe from a Nohrian attack. Mokushujin led by Kotaro himself ambushed them, but in the end they were defeated and Kotaro was slain. As it was unlikely the other Mokushujin would take kindly to Kotaro's death, a messenger was sent back to Castle Shirasagi in Hoshido to warn travelers to avoid the kingdom.
Later, as the party traveled upriver in Nohr to reach the Demon's Fall, they received a weeks-old message from Yukimura via pegasus courier warning that Mokushu had made its allegiance with Nohr known and was sending troops into Hoshido to support the Nohrian invasion. It was feared that with the addition of Mokushujin forces, Nohr would soon be able to overwhelm Hoshido's defenses and advance on the capital. However, the war ended quickly after Garon's death which prevented the combined forces from creating any impact.
Like in Birthright, Kotaro secretly formed an alliance with Nohr after recognizing an opportunity for Mokushu to profit. Garon had sent his army to invade Hoshido, with one of these groups being Corrin's army. Upon arriving in Mokushu, Kotaro greeted and explained to them that Hoshido had been harassing Mokushu ever since they aligned with Nohr.
Saizo soon attacked the group, enraged that Kaze was protecting Kotaro, much to his confusion. He explained to Corrin that Kotaro killed his father and had captured Kagero and was using her as leverage to prevent the Hoshidan army from attacking. Corrin believes Saizo's claims and demands Kotaro to show them his cells; Kotaro refused, and soon gave up his ruse, disgusted by their desire for a honest fight. He then called in a group of Mokushujin to kill the Nohrian army and blame it as a "tragic accident", but he was killed in the ensuing battle and Kagero was liberated. If either Saizo or Shura engage Kotaro in battle, they will call him out either on the former Saizo's murder of his father or the destruction of Kohga, and attempts to kill them, but fails and is killed by them.
It is unknown what happens to Mokushu after the battle, though they likely disbanded after Kotaro's death.
As in the other two paths, Kotaro allied himself with Nohr. Corrin and their small army pass by one of Mokushu's forests where they find a smoke signal, which Kaze interprets as a warning sign to keep allies away from the area. Corrin, not wanting to leave Saizo behind, heads into the forest to assist Saizo.
Saizo, Reina and Orochi were in the forest to search for Kagero, who had been captured by the Mokushujin, led by Kotaro. In the ensuing battle, Saizo would encounter Corrin and now confirming that they had no ill intentions, joined their army alongside Reina and Orochi and killed Kotaro. It is assumed like in Birthright, Mokushujin forces assisted the Nohrians in their invasion of Hoshido.
Known people from Mokushu
- Kotaro - Daimyo of Mokushu