Festro is purple with green eyes, two large tusks, and 2 smaller fangs in between. He is quite muscular and only wears a pair of briefs and a pair of brocro sneakers. He has black hair(spikes) and a bald spot at the top. Festro also has purple knuckles on his fingers.
Festro is brash, crude, selfish, and inconsiderate. He has the personality of your typical college frat boy, as all he wants to do is slack off and party. He rarely takes responsibility for any of his actions and is usually taking advantage of his friends.
Despite his disgusting behavior, Festro has moments where he owns up to his mistakes. He also has moments where he will do anything to defend his friends.
Funstro is Festro's split personality. If you pull out one of Festro's teeth, he will turn pink, have a happier voice, and act nicer and more playful and happy. Funstro is always wanting to have fun and never wants to take a break from it ever.
If you pull out both of Festro's teeth, he will turn big and red and turn into an evil monster named Fightstro who is angry and mean and is always wanting to fight with people.
- Fart - They constantly clash, despite being good bros. Fart is more refined and reserved compared to Festro who is brash and crude. Sometimes, Fart will agree and go along with some of his shenanigans. They even share a few "bro" moments (when Fart puts his arm around him in Party Slog).
- Dingle - Sometimes Festro will treat Dingle like more of a house pet and other times he will be more of another person to him. Either way, they are always good friends and Dingle is very loyal to Festro
- Slog - Festro and Slog have a strange relationship. At times, Festro will laugh at Slog's pain (as shown in Colonel Monster's Monster Time Pizza Palace when he laughs at Slog being held up to the funhouse mirror and in What It Do Nephew? when Slog was used to give Dingle a wet willy by Festro's Nephews). At other times, there seems to be a strange adoration both on Slog's end (when he offered to lick Festro's feet in Dingle Come Home and when Slog was found in Festro's underwear while he was still wearing them in Just For Kicks) and on Festro's end (watching Slog while he sleeps as told by Slog in Teleport-O-Potty, having strange nightmares about Slog's hand in Nightmare Sauce, and being the first one mesmerized by Slog's amazing abs in Party Slog). Slog seems to care alot about Festro (as shown in Colonel Monster's Monster Time Pizza Palace when he kept his promise to Festro and seemed to be the most concerned about Festro and his toothache in Funstro), but Festro doesn't seem to reciprocate the feelings in full.
- Gweelok - This one is another strange relationship. Gweelok and Festro constantly clash, much like he does with Fart. However, unlike Festro and Fart's clash of personalities and demeanors, Gweelok and Festro differ greatly in intelligence and in priorities. Festro constantly makes fun of Gweelok for having an interest in nerd culture and computers, constantly refering to it as "geek stuff". Gweelok doesn't hesitate to belittle Festro at times. However, like Slog, Gweelok seems to care more about Festro than Festro cares about him. This could be because Gweelok takes pride in being smarter than the other disgustoids he lives with, thus helps Festro out as much as he can to verify to himself how much they need Gweelok around. Festro seems to have a strange adoration for Gweelok just like he does for Slog (has a tatoo of Gweelok on his back that has a banner around it that says "Love" in What It Do Nephew? and becomes completely bent on making sure Gweelok spends bro-time with his bros rather than try to make a compromise on doing the things Gweelok likes as shown in The Bet)
- Festro has alot of Tattoos on his back that are a snake on a dagger, a heart that says MOM, a picture of Gweelok with a banner around him that says "Love", and a sign that says "Insert Coin" with an arrow pointing down to his butt-crack. Although he has all of these Tatoos on his back. They are never shown anywhere else in the show.
- Cyber festro is a clone of festro from the future. The only thing different is cyber festro is robotic battle tank But instead of strings of hair like festor he has strings of antennas And speaks in a mechanical voice. He has festro's initial on his chest. He also does not have any legs but instead of legs, He has wheels. Like cyber dingle he is a machine like battle tank and is equiped With laser cannos and can release pinkish purple laser beams
- Like most main characters of TV shows, Festro does the most talking of all of the characters. Dingle does the least talking of the 5, however his voice actor is not neglected because he is the same person who voices Festro.
- His white teeth are not seen when his mouth is shut.
- He has had the most detailed close ups in the series so far. Most of them are from the episode "Stealing the Sun"
- Festro has other personalities. There is Funstro, who is triggered by pulling out one of his tusks and then there is Fightstro, who is triggered by pulling out both his tusks.
- As many of the main Disgustoids (expect Fart) are based on animals, Festro somewhat resembles that of a walrus mixed with an echidna.
- He calls says "going boom boom" rather than "going to the bathroom"
- In Nightmare Sauce, Festro does not like Mayo, but in 7,002 he does.