So how about another little wager?
Xibalba is the secondary antagonist turned anti-hero of The Book of Life. He is an ancient, immortal god, the dark ruler of the Land of the Forgotten and the husband of La Muerte. He is introduced when he makes a bet with La Muerte about who the mortal girl Maria would marry - Manolo or Joaquín.
Xibalba is made out of black tar and ectoplasm, with green eyes and blood-red skulls for pupils. He has a pair of large, black angel wings . He wears black gloves, a regal black cloak covered by a conquistador armor, and a silver crown with horns sprouting from the both sides, topped with black wax candles lit with green flames. Xibalba has a white moustache and beard. Xibalba's fingers are long, spindly and appear to be razor sharp.
When assuming a mortal disguise, he tends to take on the form of an elderly man.
Xibalba appears on the surface as sly, cunning and cruel. He is a manipulative trickster who will resort to lies and cheating to get his own way such. Despite this, he is not pure evil, rather mischievous than malevolent. He is very suave in manner and tends to be well spoken.
He believes that there is little to no good left in humanity and that it is beyond redemption. This may or may not be down to the jaded view he sees from his realm, the Land of the Forgotten.
He claims that the reason he meddles in mortal affairs is because it is the only fun he gets outside of ruling.Though he is calm and confident, he is too proud of himself. When Manolo angered him by shouting "He will pay for what he has done", Xibalba talks and approaches Manolo with pride stating " No one in any of the realms has ever talked to him in such a way and survived ", taunting him.
Despite his actions throughout most of the story, he truly does care for his wife, La Muerte and will attempt to please her, particularly towards the end. He also gains some form of respect for mortals who impress him. He's quite capable of selfless love and admitting when he's been proven wrong.
Xibalba is extremely powerful, as expected from an immortal god. He is shown to be very adept in magical activities. It is also shown that Xibalba is deceitful, cunning and very intelligent, being layers of devise elaborate plans that tilt the balance in his favor. Your knowledge of a person's nature makes it easy for him to manipulation.
- He can quickly teleport from one place to another by transforming himself into a gooey puddle of black tar.
- He is capable of floating without moving his wings to suspend himself in the air.
- He can transform into anything he wishes to be; as in an old man or a guard of the Museum.
- His physical strength is worlds beyond a mortal, as shown in the part where Manolo infuriated him and Xibalba effortlessly sent Manolo flying with a flick of his finger.
- With the arcane magic he possesses, he can resurrect any soul he wish with the help of The Queen of the Land of the Remembered, La Muerte, and the Keeper of Balance, the Candlemaker.
La Muerte is Xibalba's wife. They have a complicated relationship due to their different beliefs and the completely different natures of the realms they rule. La Muerte believes that mortalkind still has some good in it while Xibalba believes there is no good.
Xibalba truly loves his wife and he quite literally melts at her touch. However, he has become very insecure around her ever since he cheated in their previous wager. Xibalba has shown to regret that decision and was more than willing to enter a new bet with her in order to keep her interested.
In the end, after Manolo and Maria are finally married, he gave La Muerte a heartfelt apology for his behavior and asked her to forgive him. She gladly accepted and pulled him in for a passionate kiss. In the present day, he is still on good terms with La Muerte, apparently having renounced his old ways forever and redeemed himself once and for all. When the children from the museum tour leave, he and his wife share a tender moment and a very passionate kiss.
They have not been seen to interact much on the screen. At one point the Candlemaker asked if it could slap to Xibalba after La Muerte and Carmen; although the tone of the guardian is more comical than hostile. Near the end, The Candlemaker embraces both La Muerte and Xibalba, proving he has no grudge against for the latter's trap in his bet with La Muerte. Xibalba, on the other hand, seems to find it irritating and annoying, but tolerable.
He is the older brother of Xibalba. Both have a sibling rivalry . Xibalba usually makes bets with the Chamuco; one of which ended with the champion of Xibalba, Captain Mondragón, being sent to the Land of the Unknown.
She is the twin sister of La Muerte. There was a time when Xibalba was interested in her and tried to woo her. But by the time she began to pay attention to him, Xibalba had already fallen in love with La Muerte. 
- He is made out of tar and everything icky in the world.
- According to animator and director Jorge R. Gutierrez on his Twitter account page he based Xibalba on the Aztec god of the dead, Mictlantecuhtli, who was one of two rulers of Mictlan. Mictlantecuhtli rules Mictlan alongside his wife, the Aztec goddess of the dead, Mictecacihuatl.
- His name comes from the Mayan word or term for the Mayan underworld, Xibalba, which means, "place of fear."
- Xibalba was once a knight in the heavens but he got cocky and was punished.  
- Xibalba dated humans before he met La Muerte and that's why he feels about humanity the way he does.
- Xibalba is European. He came over with the conquistadors.
- Xibalba and La Muerte met on earth at a party where both pretending to be human.
- Xibalba discovered La Muerte's fondness for wagers when he made a bet that he will win her heart, which he did. 
- Xibalba is a few centuries older than his wife, La Muerte However he is younger than The Candle Maker.
- Xibalba knew Joaquin’s father very well, Captain Mondragon had won him a previous wager with his wife La Muerte. 
- Xibalba's blood-red skull eyes can swivel in Xibalba's eye sockets depending on what direction Xibalba is facing.
- When he and La Muerte kiss at the very end of the movie, his black wings and her hat form The Sacred Heart (El Sagrado Corazón).
- La Muerte's nickname for Xibalba is "Balby."
- Though, Xibalba has wings, he doesn't necessarily need them to fly. 
- Apparently, when he touches a mortal, the person dies.
- He was completely faithful to La Muerte while they were separated.