Giyuu always wears a stoic and unbothered expression on his face. However, he has a reserved personality and a very strong sense of justice with no tolerance towards those who don't know their own limitations and throw away their lives. Despite letting Nezuko live due to Tanjiro's persistence, he shows zero hesitation when killing other demons and has no respect or mercy towards them like most Demon Slayers. Even so, Giyuu violated the Demon Slayer Corps' code of conduct without hesitation to protect Nezuko during Shinobu's attempt to kill her. This implies that he doesn't completely despise demons as some other Hashira do and is willing to make an exception for a demon by letting them live if they don't kill and eat humans. This shows that he is more pragmatic in dealing with demons rather letting his hatred cloud his judgement. He appears to have a complex with what others think of him. He is a man of very few words and has trouble interacting with others, so he usually keeps himself at a distance.

Beneath his seemingly unemotional and aloof attitude, Giyuu suffers from an inferiority complex. Despite his stoic nature, he is shown to be protective and caring towards those he is close to and considers his friends. He has been shown to lose his composure and usual stoic demeanor when those he cares about are in danger. However, Giyuu appears to be particular in who he shows emotions for. However, he will not let his personal relationships get in the way of his duty.

If you could sound similar to his English VA, Johnny Yong Bosch, that would be great, but it is not required!

English VA Example: https://youtu.be/Vj-icfTsq5Y -spread throughout the clip