In contrast to his brother Kaze, who is very calm, Saizo is brash and temperamental. He also becomes very frenetic when provoked, experiencing tremendous surges of passion that compel him to behave irrationally. This fact is made particularly evident in Chapter 17 on the Conquest route, where Saizo, guided by his feelings of seething hatred towards Kotaro, blindly throws himself into the heat of battle in a bid to exact vengeance on the man responsible for his father's demise.

Saizo has also been portrayed to be extremely cold and unfriendly towards people whom he is unfamiliar with, a fact that extends towards his allies. This is not without a cause, however; given his occupation as both a spy and one of two personal bodyguards of Ryoma, it is thus important for him to maintain a hostile attitude as a measure of caution. Saizo's careful vigilance is made especially evident through his initial support conversations with people like Azura and the Avatar, where his inability to trust anyone with a Nohrian background causes him to constantly keep a close eye on their actions under the justification that they could be plotting something sinister. However, he will acknowledge them properly if they have proven themselves to be friendly; in his supports with Azura, for one, she gains his trust by healing him while he is wounded and with Laslow when he protects Ryoma.