Armatization (神依化 Kamui-ka?, "Divine Reliance Transformation") is a gameplay mechanic exclusive to Tales of Zestiria that enables a human and seraph to access the armatus (神依 kamui?), also known as Divinity in Tales of Zestiria the X.
Only the characters Sorey and Rose can perform armatization, which fuses either of them with a chosen seraph partner to produce a powerful hybrid form called the armatus. This form can perform hidden and seraphic artes indicative of the element the seraph represents and loses access to martial artes. While in this form, the stats for the human and seraph characters are combined, and they gain special abilities unique to the fusion: the character can wield a large sword and employ fire-based magic (Lailah), shoot water arrows using a bow (Mikleo), use stone fists and summon stone pillars (Edna), or gain blade-like wings and summon whirlwinds (Dezel/Zaveid).
A character can swap out their seraph partners while not in this form, and both characters capable of armatization can be in this form at the same time. If the human character is knocked out, activating armatization will resurrect them if their current seraph partner is still active. When the fusion ends, the combined form's BG is split evenly between the participants.
With the story, armatization is the Shepherd's power that they can share with Squires who have high enough resonance. The resulting armatus is based on the divine artifact used to form the pact. The human needs to call out the seraph's true name to activate it, and as seraphim guard their true names, it requires a bond of trust. Sorey takes a while to learn how to activate the armatus at will, as he is able to enter it but has difficulty leaving it on its first use. Rose is able to pick up armatization easily because Dezel has spent years periodically possessing her body, leaving her susceptible to spiritual influences. Heldalf is able to armatize with Maotelus during his final confrontation with the group.