Taiyang was previously a student of Beacon. He graduated from the school alongside the rest of Team STRQ.
Taiyang was a member of Team STRQ.
Taiyang is mentioned to be a teacher at Signal Academy.
Yang is Taiyang's elder daughter with Raven Branwen and the two seem to have a happy father-daughter relationship. Yang also has a (slightly) better relationship with him than Ruby. According to Ruby, he taught Yang her fighting style.
Following the Battle of Beacon, when Ruby brought up the subject of Yang's welfare, though he knows his daughter is emotionally devastated, he maintains that she would recover, once she adjusts to her current condition. He lets her take it at her own pace, not pressuring her to try the robotic arm out when she isn't enthusiastic, and letting her be while she takes control of her own reaction after a flashback left her panting and scared.
In "Family", Tai is shown to butt heads with Yang, saying that she is still inexperienced and not fully prepared for the world's challenges yet. Nevertheless, the two are able to have pleasant interaction, sharing laughs together and conversing with Bartholomew Oobleck and Peter Port. Tai encourages Yang to begin moving on despite her trepidation and unease, and is willing to be with her to help her in the process.
When Yang explains to Blake what happened after Summer died, she tells her how she had to be the one to pick up the pieces of their family following Tai's extensive depression. This indicates that Yang had to fill in for both her father and stepmother until Taiyang recovered enough to function as a father again. Despite this, there seems to have been no lasting enmity between the two, with Yang understanding why her father broke down after losing his second love, indicating a deep level of understanding between father and daughter.
Taiyang's younger daughter with Summer Rose. Though some of his personality quirks annoy her, such as his overprotective nature and insistence on her making friends and growing up, which Yang emulated in "The First Step Part 1", the two seem to have a healthy and happy father-daughter relationship.
In "End of the Beginning", Taiyang is at Ruby's bedside and demonstrates genuine relief when she regains consciousness. However, when divulging details about what had happened with Ruby and the Wyvern, he seems hesitant when Ruby further inquires about what she could not recollect.
Later, when Taiyang discovers that Ruby has left for Haven Academy, he madly dashes through the house, though he is ultimately unable to catch his daughter.
After several months have passed, in "Family", it is shown that Taiyang wants to bring Ruby back home, but is unable to since he feels that he has to look after Yang. This caretaking mainly takes of the form of being there for Yang emotionally while she copes with the loss of her arm and the resulting depression, and later by training with her to allow her to adjust to moving and fighting with her robotic arm, as well as sharpening and refining her combat skills.)
Despite his concern over Ruby, he made no attempt to bring her home after Yang left in search of Raven (as a means to find Ruby.) This may indicate his acceptance of Ruby's determination to pursue her goals.
Taiyang has not been in contact with either of his daughters since that time, owing to the fact that they have spent most of their time since leaving traveling across Anima through the wilderness, meaning that Taiyang does not know how to get in contact with them (he is unable to call either of them on their Scrolls due to the destruction of the Beacon Academy CCT Tower.)
Zwei is Taiyang's pet dog. Taiyang is shown to be affectionate to Zwei, petting him after Zwei passes him a towel.
Summer was Taiyang's teammate, along with Qrow and Raven. Sometime during the first two years following the disappearance of his first significant other, Raven, Taiyang started a relationship with Summer that would result in the birth of his second child - Ruby.
Not much is known about how the two interacted, but after her presumed death he suffered an emotional breakdown, which affected him for years afterwards, causing him to become withdrawn from even his own daughters, according to Yang. During her visit to her mother's grave in Round One Ruby expressed the opinion that Taiyang misses adventuring with her indicating that the two greatly enjoyed adventuring together.
Raven was one of Taiyang's teammates, along with Qrow and Summer Rose. The two at some point entered a relationship that evolved into a marriage that resulted in the birth of his first daughter - Yang. Shortly after her daughter's birth, Raven disappeared and is still missing in the present. Their interactions with each other are unknown. Taiyang did not reveal her existence to Yang until after Summer's death.
Taiyang notes that she is a complicated person with many flaws. He admires her for her will, ambition and her strength. However, he also acknowledges her personal faults, which he claims greatly contributed to Team STRQ disbanding. His ability to painlessly give a balanced description of his ex-wife's character shows that he is able to assess their past with maturity and a clear mind. Nonetheless, upon hearing her presence while tending to his garden in "Haven's Fate", Taiyang shows visible frustration, indicating that he hasn't fully forgiven her for leaving him and Yang.
Qrow and Taiyang were once on a team together, along with Summer Rose and Raven Branwen. Just after initiation, Taiyang pranked Qrow into believing the skirt was part of the school uniform for the boys, too, by telling him it was a kilt. Tai also claims responsibility for Qrow's popularity with the girls at school on account of the skirt showing off his legs and catching their attention.
Although years later Qrow's sister unexpectedly left Taiyang, Qrow has maintained so close a relationship with Taiyang that both of his children refer to Qrow as their uncle, although only Yang is his true biological niece.
Taiyang has a very different parenting style from Qrow. Taiyang is much more protective of his daughters, often not telling them the full story. However, Qrow eventually tells Yang her mother's whereabouts and informs Ruby about her silver eyes. Though Taiyang has told Qrow numerous times not to talk about Raven, he knows that Qrow finally did. Qrow is far more direct than Taiyang in how he addresses Yang and Ruby's queries regarding their origins and abilities respectively, showing that while Taiyang loves and acknowledges both of his children and respects their abilities, Qrow is far more direct and frank with the girls. Regardless, Taiyang seems to appreciate how close Qrow is to his daughters, even if he does not necessarily see eye-to-eye with Qrow's approach to the girls' upbringing. Qrow also seems to have been the one who told Taiyang that Raven or Summer was not going back.
They both have been said to teach at Signal Academy and are colleagues.
Though they have not interacted onscreen, Taiyang went to see the general on his daughter's behalf, and he was surprised to learn Ironwood had already commissioned a prosthetic arm for Yang as a reward for her bravery during the Battle of Beacon. His tone indicates a respectable amount of graciousness for the General's gift to his daughter.
Taiyang gets along with them very well, as seen in "Family" when the three laugh and share stories in Taiyang's kitchen.
According to Raven, Tai knows many of Ozpin's secrets, which were revealed to him and the rest of Team STRQ during their time at Beacon. He likely knows of Ozpin's ability to reincarnate, hence why he referred to him as simply "missing" in "End of the Beginning".