Martin Zignard is an Alter user and a prominent figure within the organization known as HOLY, which operates on the Lost Ground. He is an American immigrant who arrived in Japan and is recognized as the first known Alter user, though he refrains from using his ability for most of the story. Zignard serves as the commander of HOLY, the unit responsible for policing native Alter users on the Lost Ground. His primary motivation stems from a deeply held conviction that Alter users need protection from the widespread discrimination and persecution they face from ordinary people. To that end, he founded HOLY as a safe haven for Alter users, believing that order and control are necessary to prevent chaos and ensure their survival.

In terms of personality, Zignard is portrayed as a noble and principled man with strong beliefs about his cause. He is methodical, authoritative, and willing to make difficult decisions for what he sees as the greater good. However, he also harbors a personal agenda that becomes clearer as the series progresses, revealing a more manipulative and calculating side. He believes that those with Alter powers who refuse to fall in line with HOLY's vision must be contained or eliminated, viewing them as threats to societal stability.

Zignard’s role in the story is that of a major antagonist whose influence shapes the conflict between HOLY and the native Alter users. He is responsible for creating advanced technology and weapons used against rogue Alters, and he often leads operations to capture those who resist HOLY’s authority. His key relationship is with Ryuho, the elite HOLY agent. Zignard eventually confronts Ryuho directly, revealing both the full truth behind HOLY’s founding and his own hidden Alter ability. This confrontation is a turning point in Ryuho’s character development, forcing him to reassess his loyalties and motivations.

Zignard’s character undergoes significant development when he finally activates his Alter, which he had never used before. His Alter, called Alter Alias, manifests in two parts: a metal alloy that covers his upper chest and arms, and a separate, independent form named Alias that can project highly compressed air as both a defensive shield and powerful shockwaves. Because his Alter had been heavily refined and left dormant for so long, using it comes at a severe cost: it causes him to age rapidly, turning him from a man in his early twenties into an elderly figure over the course of a single battle. This sacrifice underscores his dedication to his cause, but also highlights the tragic extremes he is willing to go to in order to maintain control. Ultimately, Zignard serves as a cautionary figure, embodying the dangers of rigid ideology and the personal toll that absolute conviction can exact.