Matsu Maeda anchors the Maeda clan narrative as Toshiie Maeda's wife and adoptive mother to their nephew, Keiji Maeda. Her highly responsible, disciplined nature counters Toshiie's impulsiveness, yet she exhibits unwavering loyalty and affection toward him. With Keiji, she adopts a stricter approach, convinced of his untapped potential and determined to forge him into a capable warrior. This duality earned her recognition among fans as embodying the "ideal housewife" archetype, merging domestic dedication with formidable capability.

Her background showcases significant intelligence and proficiency in both literary and martial arts. Initially introduced wielding a katana styled after Kenshin Uesugi, she later shifts to a naginata as her primary weapon. She uniquely summons and commands animals for combat and support: Jiroumaru the boar executes charging attacks, Taromaru the hawk delivers aerial strikes and enables gliding, Saburoumaru the mole impedes enemy movement, Goroumaru the bear serves as her mount, and Shiroumaru the wolf draws enemies toward her. Her personal inscription amplifies these summons, doubling their damage. In combat, she employs rapid stabs ("Comet Pierce"), dashing slashes ("Soaring Star"), spinning tornado attacks ("Heavenly Nebula"), and a revision skill leveraging summoned animals to gather foes.

Narratively, Matsu's early involvement centers on familial duties, gathering ingredients to prepare meals for Toshiie and Keiji. Her role escalates dramatically when Yoshiaki Mogami kidnaps her, coercing Toshiie into allying with the Eastern Army. This captivity forces Keiji into a pivotal dilemma: abandoning the Western Army and Magoichi Saika to directly appeal for her release, or remaining with Magoichi to confront Tokugawa Ieyasu at Sekigahara while Magoichi rescues her. Her capture and rescue thus directly influence the strategic choices and factional alignments of key Maeda figures.