Up until his disappearance in "End of the Beginning", Ozpin served as the headmaster of Beacon Academy.
Ozpin is the leader of a group whose goal is protecting the world from dangers that are kept secret from the public. Other members of the group include Glynda Goodwitch and Qrow Branwen, as well as the leaders of the other three academies - James Ironwood of Atlas Academy, Leonardo Lionheart of Haven Academy and the headmaster of Shade Academy.
Four unnamed daughters
Not much interaction has been shown between him and his daughters, but he loved and cared for them deeply.
Two unnamed children
As the Settler who initially constructed Ozpin's cane, he had two children with his second known wife, and presumably loved them a great deal, as he headed out to protect their village against an invasion of Grimm.
Glynda is a fellow staff member at Beacon Academy. She is often seen alongside him when addressing students. Based on the blunt and honest manner in which she usually speaks to him, the two have clearly known each other for a while. Their history includes both being a part of Ozpin's group, a brotherhood dedicated to protecting Remnant.
Ozpin has known Qrow for years, as implied in Ruby Rose's interrogation in "Ruby Rose". Ozpin was certainly present on Qrow's first day at Beacon Academy. In "Black and White", the two men are continuing an apparently-secret correspondence regarding someone code-named "The Queen".
When the two meet with Glynda and Ironwood in Ozpin's office, Qrow mentions that Ozpin invited Ironwood into the group's inner circle, implying that Qrow had Ozpin's trust far earlier than Ironwood. After Ozpin disappears, Qrow sees himself as the one to step up and take responsibility in Ozpin's place. This includes taking Ozpin's Cane, which he later gives to Oscar Pine. This act indicates Qrow's awareness of more secrets about Ozpin than the show has revealed, particularly with the words "It's good to see you again, Oz."
It is revealed in "Rest and Resolutions" that Ozpin granted Qrow and Raven the ability to turn into birds to gather information and find out where the Maidens are. The two men seem to have a mutual level of trust, as Qrow quickly defends Ozpin from Yang's accusations.
In "True Colors", Ozpin and Qrow discuss their situation with different views: Ozpin being optimistic and Qrow pointing out their disadvantages. After Lionheart's call, they both become very suspicious about the Haven headmaster.
In "Uncovered", Ozpin begins to lose the loyalty of Qrow, who allows his niece to do what she believes is right, and then fully loses it in "So That's How It Is". Once Ozpin admits that he's never had a plan to defeat Salem, an enraged and betrayed Qrow punches his former mentor into a tree.
Qrow goes on to say that he was cursed and nobody wanted him until Ozpin came along and gave him the means to do good in the world. Ozpin appeals to Qrow that he was doing good but Qrow rejects this and calls meeting Ozpin the worst luck of his life. This causes a distraught Ozpin to admit that maybe his former pupil was right before retreating into the depths of Oscar's mind.
Ozpin and Ironwood seem to be very good friends, speaking in manners unseen with most others. This indicates a rather personal level of familiarity. However, Ironwood's methods and views about security tend to clash with Ozpin's, resulting in the two regularly being at odds with one another. Though Ozpin considers the general misguided, he also notes that his heart is in the right place.
Ironwood comments that he has served under Ozpin for years as part of his secretive group; despite their differences, Ironwood still answers to Ozpin.
Lionheart was one of Ozpin's trusted lieutenants, but Ozpin starts to doubt him in "Unforeseen Complications" after learning that he is not following several of his instructions. Sensing that something is wrong, Ozpin decides it is best not to let Lionheart know that Oscar Pine is his new reincarnation. His suspicions increase in "True Colors" when Lionheart claims to have a raiding party ready to find Raven's tribe.
In "The More the Merrier" he is shocked to discover that his suspicions were not misplaced and that Lionheart has been acting as an informant for Salem.
Despite Leo's fall to Salem's side as her informant and operative within Haven Academy, Ozpin enabled Lionheart in the official story of the Battle of Haven Academy to be remembered as a hero. However, Ozpin is still greatly wounded by Leonardo's betrayal, revealing in an emotional outburst in "Uncovered" that he was not the first to turn against him. Nevertheless, he believes that Leonardo deserves to be remembered for his lifetime of good deeds and civil service, rather than for the damning actions of his final years.
Ozpin seems to take a special interest in Ruby. When the two first meet, he is intrigued by her silver eyes, knowing about her lineage, before commenting on her level of skill with her scythe, Crescent Rose. He also seems interested in Ruby's motivation for becoming a Huntress, in that she wants to help people. He is so impressed by Ruby that he allows her to skip two years at Signal Academy in order to enroll at Beacon Academy.
Even after her enrollment, he continues to watch over her, completely ignoring Glynda's report during the Beacon Academy Initiation in order to watch Ruby's progress on his Scroll. He is also seen observing her in "Black and White".
During the year at Beacon, Ozpin appears at her side a number of times. After Weiss Schnee starts making Ruby question her appointment as team leader, Ruby asks Ozpin whether he made a mistake appointing her as the team leader. The headmaster gives Ruby a pep talk, advising her that being a leader means acting her best so that she will be respected by her teammates. He then confides in her briefly, stating that he's "made more mistakes than any man, woman, and child on this planet" but believes his appointment of her as the team leader is not one of them. At the Beacon Dance, he advises Ruby to enjoy herself, pointing out that fighting and dancing aren't very different.
He also covers up for Ruby, cutting off Glynda's question when Ruby tells him of a possible hideout in the southeast of Vale despite Ruby previously saying that Cinder did not say anything to her. He also asks her to be discreet about what they have discussed.
After Team RWBY is unable to get their mission in the southeast, Ozpin hints that he is aware that they have been up to extracurricular activities. He makes Ruby self-conscious and uncomfortable while listing unexplained events from "Black and White", "Extracurricular", and "Painting the Town...", all while claiming he'll never find exact answers. Ruby's mood changes, however, when he volunteers to bend the rules for them to get their mission since he suspects that they would make their way there anyway.
When Ozpin reunites with Ruby in "Unforeseen Complications", he apologizes to her and Team RNJR for the hardships they have gone through, despite Ruby saying that it is not his fault. To prepare her and her friends to fight Salem, Ozpin decides to train her in hand-to-hand combat.
In "Necessary Sacrifice", Ozpin describes Ruby as remarkable to Oscar. While he notes that she was one of the best Huntress at Beacon in some ways but not in many others, he remarks that she possesses a "spark" that inspires others even in the darkest of times.
In "Uncovered", Ozpin begins to lose the faith that Ruby has placed in him. After she summons Jinn, he pleads for Ruby to not ask Jinn about his secret, but to no avail. In desperation, he lunges towards her before everything goes white.
The two are not shown interacting together during the Beacon Arc, though it is revealed in "Known by its Song" that Weiss knows of what she believes is his true past.
When they finally meet in "Rest and Resolutions", Weiss is startled by what Ozpin reveals to them, basically confirming what Raven told her and Yang earlier.
Though after the trainwreck in "Uncovered", Weiss joins Yang in scrutinizing Ozpin over failing to keep his word about not keeping any more secrets.
Ozpin is aware that Blake is a Faunus, and also seems to suspect Blake having some affiliation with the White Fang as he questions her on how she had known where they would attack. In addition, he notes that she is one of only a few people who managed to enter Beacon Academy without the years of preparation to pass the rigorous entry exam.
He ends the questioning by offering her a listening ear, should she ever need to talk to him.
The two are not shown interacting together during the Beacon Arc.
When they finally meet again in "Rest and Resolutions", Yang confronts him on turning her mother and uncle into birds. When she learns they chose and accepted the power, she relents. Yang agrees to keep fighting on the condition that Ozpin doesn't withhold any more pertinent information.
Though after the trainwreck in "Uncovered", Ozpin finds himself scrutinized by Yang for failing to honor his promise about not keeping any more secrets along with covering up Lionheart's treacherous actions as Salem's informant, which in turn makes Ozpin quite testy, who goes on to defend Lionheart despite turning traitor. When Yang vows not to turn his back on him, Ozpin blurts out that Lionheart said the same thing, and goes on to defend his methodology.
Despite Glynda's protests about Jaune, Ozpin decides to make him the leader of Team JNPR in "Players and Pieces", much to the boy's surprise. In "Unforeseen Complications", Ozpin decides to help Jaune in unlocking his Semblance. When Jaune laments about not finding his power in "Lighting the Fire", Ozpin tells him not to worry, as his journey is far from over and unlocking his Semblance will not be the end of it.
Ozpin has thought highly of Pyrrha since she began attending Beacon. He thinks of Pyrrha as strong, intelligent, caring and ready to be a guardian figure. In "Fall", Ozpin chooses Pyrrha to become the next Fall Maiden but allows her to accept or decline. In "Heroes and Monsters", Ozpin defends Pyrrha from Cinder and yells at her to get Glynda and Qrow to help him, not wanting her to risk her own life.
Ozma, Ozpin's original form and identity, was the one who freed Salem from imprisonment by her cruel father. Salem deeply loved Ozma and grieved horribly upon his death by the way of illness. Ozma was important enough for her, to decide to go against the gods in order to get him back.
When the God of Light offered him the chance to return to the living, Ozma initially rejected the offer, believing that it would not be the same without Salem by his side, showing how much he cared for her. The only reason Ozma accepted was because the God of Light told him Salem was still alive. Though when the God warned him that Salem was no longer the woman he loved, he still took the offer if only to see what had become of her.
When Ozma and Salem encountered each other again centuries later, despite the many changes they'd gone through, the two instantly recognized one another and shared a heartfelt reunion. Though when they discussed their circumstances, Ozma lied to Salem, afraid she would feel betrayed once she learned why he had been reincarnated. Together, the two of them used their powerful magic to portray themselves as Gods to Humanity and the two formed a kingdom together. The two finally got married and formed a happy family, with Salem giving birth to four daughters.
However, Ozma's lingering guilt overtook him and he confessed to Salem why the Gods brought him back to life. Sadly, Ozma's worst fears about the God of Light's assessment of Salem's change proved true when Salem proposed a plan to exterminate Humanity and replace them with a species in their vision. Horrified at what she had become, Ozma tried sneaking their daughters out of the castle but Salem caught him in the act. The two fought a lengthy battle that resulted in the deaths of their daughters. Flipping an injured Ozma on his stomach after he tried crawling to safety and stomping on his chest with her foot. Salem condemned Ozma for choosing his promise to the gods over their family, love and everything they had created, Salem burned him alive. Thus the centuries-long feud between the two lovers began.
However, a millennium later, she is heard calmly and respectfully conversing with Ozpin in the episode "Ruby Rose". Ultimately, however, in "End of the Beginning", Salem affirms that she intends to watch Ozpin burn, but only after she destroys everything he has built. Judging from comments made by Cinder during the events of "Heroes and Monsters", Salem now deems Ozpin exceedingly arrogant. In every aspect of their conflict over the Relics, Salem appears to hold a great deal of contempt towards the man. Given that their conflict is thousands of years old, her enmity for him has been given a great deal of time to ferment into a festering hate for Ozpin.
Cinder Fall is the main enemy of Ozpin and his group during the first three volumes. She successfully steals the Fall Maiden's powers that Ozpin's group tries to protect. They both meet face to face in "Heroes and Monsters" where she expresses her disdain for him and prepares to fight against him. In "End of the Beginning", both finally clash in the vault underneath Beacon, resulting in Ozpin's death. Cinder later reports her victory to Salem, though Salem questioned her at least one more time for the sake of certainty. However, she is shocked to find out that Ozpin is still alive and reincarnated into his new vessel.
Ozpin informs Oscar in "Kuroyuri" that Hazel is a man from his past who is not to be taken lightly.
In "Vault of the Spring Maiden", it is revealed that Hazel despises Ozpin because he blames him for the death of his younger sister Gretchen, who strove to become a Huntress at Beacon Academy and died on a training mission. Due to their previous history, Ozpin believes that Hazel is too emotionally devastated to be reasoned with, preferring to resolve their enmity by way of combat in spite of Oscar's attempts at diplomacy and reconciliation.
A fellow staff member at Beacon, Port shows a deep trust and admiration for Ozpin when defending him to Weiss, stating that he served under the headmaster for years; in all that time, Ozpin never led Port astray.
Ozpin first speaks to Oscar in "Family", but it is not until "Punished" that it is revealed the conversation takes place inside Oscar's mind. Ozpin informs Oscar that their Auras and souls are combined and Oscar's thoughts are now also his. Eventually, Oscar comes to accept that they are one and the same, tentatively referring to Ozpin's Cane as "my cane" and telling Team RNJR they know him as Professor Ozpin.
Ozpin has taken to mentoring his latest incarnation, and, in turn, Oscar has picked up the habit of conversing with Ozpin during moments of self-doubt, relying on Oz's wisdom and experience when he is at a loss of what to do. By the time of "Necessary Sacrifice", Oscar has formed a mutual trust with Oz, consulting him on Ruby's nature as a person, forming a close personal bond with one another and gaining solace in the battle against his fears of the upcoming war against Salem and her forces. According to Ozpin in "Unforeseen Complications", when he is reincarnated, it is into a "like-minded soul", suggesting he and Oscar have similar ideals. Among these is a pronounced distaste for warfare, an admiration of the pure of heart and a high capacity for empathy.
Their relationship becomes strained in "Vault of the Spring Maiden" when Ozpin tells Oscar to run from Hazel, but Oscar refuses, citing that Ozpin told him to fight. Even so, Oscar defends him from Hazel's accusations for Gretchen's death on the grounds that she made a choice. However, Ozpin renders Oscar unconscious and forcibly takes control. In "Haven's Fate", Ozpin has Oscar pass on his message to Qrow to bring the Relic of Knowledge to Atlas.
In "Argus Limited", Ozpin's request to take over Oscar's body is denied due to Oscar's anger of his lack of trust and faith in him during the Battle of Haven. In "Uncovered", Ozpin finds that Oscar is able to resist control for a few seconds, which gives the farm boy enough time to tell Ruby about Jinn.
Despite the limited shown interaction between the two, it is clear they have known each other for a long time. Jinn teasingly calls him "old man", but he avoids mentioning her to the others when talking about The Relic of Knowledge. After Ruby summons Jinn, Ozpin pleads Jinn not to reveal the truth to the others about the two questions she has left, but Jinn ignores him and answers Ruby's question truthfully, telling the heroes what Ozpin had been hiding from them.