Who's-Who tends to maintain a calm and serious disposition while around peers, like showing annoyance at their bickering. Somewhat ironically though, he has also shown himself to be loquacious at times, such as rambling on about his past while in the middle of a fight. In battle, Who's-Who tends to be derisive toward enemies, openly laughing at their or their allies' predicaments. He also feels no need to honor the spirit of a fair fight.