Siarnaq's personality is monotone and robotic, making him seem almost lifeless. He is shown to be computer-like, and his speech is capitalized, making him seem more like a Mechaniloid than a Human/Humanoid/Reploid (for example, asking to "INPUT RESPONSE" and declaring "INCOMPREHENSIBLE"). Similarly, in the Japanese version his text is written almost exclusively in katakana, which is typically used to imply a mechanical or monotone voice in that language. Other than that, he seems to have no personality at all, except being at least slightly sadistic, as when the player is defeated by him, he will be heard laughing dementedly. His laugh may show his hidden, or already shown personality, depending on the game's version. If the game is the American version, he will make a robotic and monotonous evil laugh, thus showing his robotic and cold personality. However, in the Japanese version he has a unsettling, deranged-sounding laugh, suggesting he might not be completely stable or even sane. This is supported further by his disk, which speaks of his past being wrought with betrayal.