Kaguya & Yuzuru Yamai

Kaguya: "Outgoing and outspoken, one can say that she is childish or immature. Kaguya appears to suffer from Chūnibyō, often using with exaggerated gestures and German words in an attempt to sound cool. However, she is perfectly capable to speaking normally and her act quickly falls apart if even slightly pressed upon, causing her to often be teased by others. She is also weak about sensual matters and is easily embarrassed when they are mentioned."

Yuzuru: "She speaks in a robot-like speech pattern, telling the point of her comment before speaking the rest. For example, when asking Shido to explain something, she would say "Confirm; Shido". Also, unlike with Kaguya, her speaking patterns are a genuine verbal tic and not just an act. When arguing with Kaguya, she tends to sneer at her and points out the flaws in her arguments. Overall, Yuzuru is the calmer, quieter, and arguably the more mature one of the twins, though she still has her own moments of childishness."