- "My expertise is navigating small spaces. Jean-Paul here might like the high ground, but I like the low."
- ―El Topo's introduction to his roommates
El Topo is a short man with dyed silver hair and a stealth suit with green accents and claw-like gloves with boots.
When El Topo met Black Sheep, he seemed like a calm, carefree person. El Topo was also very kind, smart, intelligent in class, and willing to play along with a joke or prank. However, he has been shown to possess a merciless side, as he was willing to leave no witnesses during his graduation heist.
He has shown hesitation in bringing harm to his allies, though, particularly Carmen and Le Chèvre. In the Boston Tea Party Caper, he silently apologized to Carmen when he was ordered by Le Chèvre to toss her overboard. In The Hot Rocks of Rio Caper, Part 2, he was hesitant to tie up Le Chèvre. Additionally, El Topo stepped forward to defend Black Sheep after pulling the water balloon prank on Cookie Booker, much to Le Chère's surprise.
By the time he graduated, he was more distant, becoming passive to Black Sheep rather than friendly. He doesn't seem to be very caught up on what he and his teammates are doing most of the time– besides Le Chèvre.
In the Carmen Sandiego: To Steal or Not To Steal interactive special, El Topo states that he is excited to be working with Carmen on their caper. When Carmen asks him if he's a VILE hater, El Topo clarifies that he really doesn't hate anyone, as he views himself and others as mere pawns in a bigger game.
- His name, in fitting with his tools, is Spanish for "The Mole". He wears mole-like robotic claws and can travel underground because of them.
- He may have gotten the idea for his code name from Professor Maelstrom, who refers to him as a 'little mole.'
- Throughout the series, El Topo exclusively goes on missions with Le Chèvre and prioritizes his partner's safety over completing their objectives, dropping everything when Zack tells him that Le Chèvre was attacked by dingos in "Opera in the Outback Caper". In Who in the World is Carmen Sandiego? he and Le Chèvre are described as inseparable, as they are rarely ever seen without each other.
- During the origami lessons, he attempted to fold a paper mole but crumpled it up in frustration.
- He is seemingly favored by Professor Maelstrom in the first novel, as he is chosen to be a volunteer in his class repeatedly.
- El Topo seems almost zen, as he doesn't really let things bother him. When he teams up with Carmen in the game, he insists there's no point in disliking her as they are both pawns in the game of life.