Cethin's personality is marked by deep resentment, cynicism, and a dark sense of humor. Once a proud knight, centuries of cursed servitude have eroded his humanity, making him manipulative and observant. He despises his masters, finding grim amusement in their hypocrisy and exploiting their weaknesses. Though powerful and dangerous, his interactions are driven by contempt and a begrudging acceptance of his cursed existence, masking any remnants of his former ideals.