"The impeccable butler who follows Diavolo around as if he were his shadow. His ability is to see both the past and the future."
Barbatos has short dark green hair with bangs reaching his eyebrows. The fringe on his left is longer, reaching his nose and has a turquoise ombre. Like all the other demons, Barbatos has painted fingernails. Barbatos's nails are a mauve purple color.
Barbatos has a very calm demeanor, although he does enjoy lightly teasing other people. He is nice towards MC and often saves leftover sweets he bakes for them. He is very loyal to Lord Diavolo, and wishes to serve him well. Diavolo has complained that sometimes Barbatos is too harsh on him. The demon brothers describe him as overprotective of Diavolo.
He also shows extreme patience for Diavolo, as evidenced in The Fantastic Three(3) chatroom interactions. He is usually calm and collected and agrees with almost everything Diavolo says. He never displays much emotion and often comes across as sarcastic.
Barbatos is also relatively friendly towards Luke, teaching him how to make pastries as seen in chatrooms, and they often bake treats together. On many occasions, Barbatos gives Luke advice for cooking, such as recommending him better baking powder brands. According to Luke, Barbatos is the greatest pastry chef in all of the three worlds (Devildom, Celestial Realm, Human World).
It seems Barbatos and Lucifer have mutual respect for one another, although Barbatos occasionally jokes about Lucifer. In some instances, he is shown being concerned over Lucifer's well-being. When Diavolo requested that Lucifer doesn't work himself too hard, Barbatos agrees with Diavolo's statement and presents an image MC took of Lucifer, overworked, to help Diavolo persuade Lucifer to get some sleep.
Barbatos takes his position as a butler very seriously. He even teaches the demon brothers intricacies about his job in the Demon De Butler event. The demon brothers believe that Barbatos could do anything, thus resulting in them frequently seeking out his help.
While typically exuding a calm demeaner, Barbatos seems impartial to being interrupted when speaking about something he is passionate about, even going so far as to throw a fork at Mammon's head for speaking over him. According to Little D. No. 2, Barbatos's smile remains in place even when he is angry. Some of the demon brothers — Mammon in particular — think that Barbatos is shady and scary, and are convinced he has a hidden room in the Demon Lord's Castle where he partakes in the act of torturing people.
- In the chat Surprising Taste, Barbatos states that he likes heavy metal music.
- Barbatos is a lover of tea, and according to Lord Diavolo in the Devilgram A Fellow Tea Enthusiast, Barbatos is a "walking tea encyclopedia."
- Beelzebub mentions in the chat Barbatos's Weakness that Barbatos does not like rats.
- In the chat What's Going On?, Asmodeus sends a photo of Barbatos "frozen in fear" upon finding a rat at the House of Lamentation.
- One of Barbatos's calls is also associated with rats.
- In the Devilgram All Because of That, Barbats refers to the rat as a "you-know-what" and says hearing the name makes his skin crawl.
Barbatos mentions in the chat That's What I Mean that he was never a child. He has the power to see the past and the future, and is able to choose from multiple realities whichever one he prefers to become the sole reality. He can accomplish these feats by opening doorways to any time and place, including the Human World and the Celestial Realm. Lord Diavolo expressly forbids him from using his power freely.
He admits to MC in The Legendary Dame Devilgram that he was once a Dame at Queen Rose's banquet. He was considered so beautiful that it caused an uproar, and piles of fan mail was delivered daily to the Demon Lord's Castle. From then onwards, he swore to never be a Dame again.
- According to the chat The Fragrance of Tea, Barbatos tells MC that due to the nature of his job, he's never had much interest or desire to wear perfume.
- According to a psychological test that Asmodeus taught Diavolo — who brings it up in the chat Behavior in Love — Barbatos "enjoys working hard for his loved one."
- In one of his dialogues when given Revelation Tomatoes, Barbatos mentions occasionally supervising fan club meetings for the student council members.
- Asmodeus confirms this when also given Revelation Tomatoes, saying that Barbatos showed up to one of his fan club's meetups.
- Barbatos mentions in The Secret Dish Devilgram that he visits the local port market three times a day to purchase ingredients.
- Despite appearing perfect at nearly everything, Barbatos has a great deal of difficulty as an actor in the Devilgram Just Be Yourself!, as he has never acted before.
- In Lesson 2-A, it is revealed that Barbatos is in a pact with Solomon.
- In Lessons 49-A, Barbatos admits to making his pact with Solomon before the sorcerer had his pact with Asmodeus.
- Through the use of his powers, he also knew that Solomon would form a pact with Asmodeus before it actually happened.
- He's the only demon currently known to have pacts with other humans, but not with MC.
- In Lesson 53, Solomon reveals that he possesses Barbatos's grimoire, which Barbatos says he trusted Solomon with of his own free will.
- In Lessons 54, whether Barbatos actually gave Solomon his grimoire or not is put into question when he admits the grimoire given to MC was a fake.
- According to Barbatos in Lesson 58-A, he became Diavolo's butler after Diavolo lured him into the Demon Lord's Castle with the promise of rare cheshire cat grass tea. He then told him that he'd not allow Barbatos to leave until he agreed to be his butler.