Penn is at a normal height with curly red hair and cyan eyes. He wears a white-with-black-sleeves shirt with a white slashed zero outlined with orange on the front, a blue plaid collar and end of sleeves, and chain mail underneath. Around his hips, he wears a black belt with the MUHU attached to it. He also wears red skinny jeans and boots with black fronts, white backs, and a yellow line above the ankle.
Penn is brave, enthusiastic, and determined. While being a hero doesn't come naturally to him, he tries his best to save the world he's in. As the leader of his team, Penn isn't very confident in his leadership skills, in general not being a fantastic leader, and sometimes he doesn't make wise calls in particular situations. Despite this, he makes sure to listen to Boone and Sashi's suggestions, along with thinking up his own ideas and giving commands. He often notices when something is illogical, pointing in out for others whether in irritation or confusion.
Although sometimes Penn gets annoyed with other people's actions, insulting and sassing them, he realizes when he hurts someone's feelings and works to make things right. In other cases, he gets distracted, loving to have fun, but whether by himself or others, he gets back on track. He cares deeply for others, especially those he's close to like his parents and friends. If he has to, he'll sacrifice what he cares about to save the day, as he genuinely wants to help others, even if it sometimes means assisting his foes.