Adam's exact history and relationship with the SDC is unknown, but given the brutal branding he received on his face, the SDC's history of amoral and abusive usage of Faunus labor, and Adam's own admittance to being severely abused by humans, its highly likely that he was once one of the SDC's workers. This eventually shaped his incredibly jaded and spiteful view on humanity as a whole. Which eventually caused him to develop an immense grudge on not only the SDC, but on the entirety of humanity.
Adam starts as the leader of the White Fang's Vale branch, making him the very person for Cinder Fall to approach with her proposition of using White Fang soldiers for her plan. Later, after enacting his coup in "Dread in the Air", Adam ascends to the position of High Leader. In "Haven's Fate", after the failed attempt to destroy Haven Academy, Adam flees to evade capture from the authorities and leaves his White Fang comrades behind. His status in the organization further crumbles in Argus Limited, where his remaining followers berated him for his defeat and abandoning their brothers. Adam orders them all to stand down only for someone to point he retreated because of Blake, resulting in Adam killing them all out of anger.
Adam Taurus served under Khan until rebelling and killing the former White Fang leader to take control of the organization. Before her death, he is shown to sympathize with her philosophy of using violence to help the Faunus but unlike her, is willing to resort to even more extreme measures and later states his desire to enslave humanity. To that end, he was willing to kill Khan in cold blood whilst thanking her for her service and using her as a martyr for his cause.
Adam was pressured into aiding Cinder's Faction during the events of "Beginning of the End".
At the end of the episode "Breach", it is indicated that Adam is aiding Cinder Fall in persuading the White Fang to support their efforts.
When they first met in "Beginning of the End", Adam appeared to dislike Cinder. He refused her offer to join together, as he did not want the White Fang to die for a human cause. After Cinder stole half of Amber's Maiden power and came back and injured several of his men, she gave Adam the same proposal. However this time he was given a choice between money and resources or death. Adam begrudgingly agrees to work with her.
Adam knows of Salem's existence, and also knew of her concern about Sienna Khan possibly opposing them. So he "remedied" the problem on his own volition by overthrowing Sienna as High Leader. Ironically, this decision would end up backfiring on both of them. After his failed assassination attempt, Blake along with her family and friends formed a miltia that ruined Adam's end of the mission to destroy Haven. It is unknown if Salem knows or cares that Adam is dead.
Despite being assigned to work together by Salem, Adam and Hazel have little to no respect for each other. Adam brought Hazel before Sienna to negotiate an alliance with Salem, but did not tell him of the coup he planned to enact should Sienna refuse their offer, citing that it was "his business". When Hazel states that no one had to die, Adam disagrees.
Their lack of cooperation is later seen in "Downfall", as Adam looks to Hazel for advice when his plans are ruined, only to receive an answer of fixing his own problem by himself. In "Haven's Fate", Adam watches Hazel as he, Emerald Sustrai, and Mercury Black escape from Haven. It's unknown if Hazel knows or even cares that Adam is dead.
Adam's ex-partner, the two shared what Monty Oum described as a mentor-apprentice relationship. The two were operatives for the White Fang. However, this connection was severed, as Blake is seen leaving him at the end of the "Black" Trailer.
Blake saw that he did not care about innocent lives, such as when he went to set demolition charges on the train despite her protest about personnel on board. His callous disregard for the lives of the crew caused the two to part ways. However, in "Best Day Ever", Blake is shown to have a sketch of him in her notebook, suggesting she still thinks of him.
Blake brings Adam up twice to the rest of Team RWBY, once about her motives for leaving the White Fang, and another time about why she was not immediately able to trust Yang's innocence after the incident with Mercury. The first time she referred to him as her oldest partner turning into a monster. The second time she described Adam as someone very dear to her who changed for the worst.
In "Battle of Beacon", as he and Blake encounter each other again, he calls her his "darling." In "Heroes and Monsters", he calls Blake "my love" and states that all he wants is her. This suggests a romantic history of some kind existed between them. However, since Adam's words are preceded by backhanding Blake across the face, genuine affection on his part is unlikely. He is specifically referred to by Miles Luna as the "crazy, abusive ex-boyfriend".
As they fight, he manipulates her emotionally and plays on her weaknesses. He rails at her about how their destiny was to change the world together and promises that she will run away again, but not until after she suffers for her betrayal. Their battle ends with him beheading Blake's clone.
In "Necessary Sacrifice", Adam displays an unhealthy obsession for revenge on Blake as he orders Corsac and Fennec Albain to have her brought to him alive and her parents are assassinated. However, he is unaware that Blake had anticipated the trap laid by her captors and managed to escape them.
In "Downfall", Adam is delighted to see Blake seemingly turn herself to him but is later angered when she and her comrades foil his plans of destroying Haven. He attacks her in rage, only to be clobbered at the back of his head. In "Haven's Fate", Adam tries to intimidate Blake by using her fear of him but to no avail as she has clearly gotten over him. After their brief fight, Adam escapes in an attempt to lure Blake and Sun Wukong away and take them down when they are alone, but Blake easily sees through his plan.
After the Battle of Haven, in "Argus Limited", Adam's hatred and obsession for Blake grows stronger. He hates it when someone mentions Blake's name, which results in him slaughtering his remaining followers upon his return to White Fang headquarters.
He finally corners her atop the Argus radar tower in "Stealing from the Elderly" and specifically blames her for his ruination. As the fight goes outside the tower and into the forest below, Adam vows to never let Blake escape again. As the two fight, Adam verbally abuses Blake, calling her a coward for running from him and telling her that if she had only "behaved", his current actions would not be necessary. After revealing his scarred face to Blake, he states that no one hurt him like she did.
In "Seeing Red", when Blake says she will stay by Yang, he reminds her that she made a promise to him to stay by his side and she never kept her word. Which only results in Yang mocking Adam, asking if Blake actually promised him or the person Adam was pretending to be. Afterwards, Adam is overwhemled after Blake and Yang manage to impale him.
Later during the events of Volume 7, it is shown that Blake still harbors feelings of guilt and confusion with Adam's death and later during "Worst Case Scenario". It's confirmed that Blake still feels immense guilt & shame at having killed him and later expressed her wish to never have to face the same choice at having to take someones else's life. This shows that despite everything he did to her, Blake never truly hated him enough to want him dead.
When Yang was heard calling out for Blake, Adam informs Blake that he would begin with Yang in his mission to destroy everything Blake loves. He provokes Yang into attacking him by stabbing Blake in her stomach. When Yang rushes him, he easily severs her right arm, then moves in to finish the job. However, Blake's interference prevents him from killing Yang.
Over a year later, Yang stops him from killing Blake by running him over with her motorcycle, and then standing before him. When she vows to hold him off, he agrees without question, intent on finishing what he started at Beacon. After a brief battle, Yang warns him to leave them be. But Adam calls her bluff, insinuating she is afraid to die protecting Blake. In "Seeing Red", during their fight, Adam keeps taunting her about her actions in the Battle of Beacon. He appears to be jealous of Yang and questions her close relationship with Blake. He was unable to control his anger, as he failed to realize Yang used her semblance to absorb his own, much to his shock and horror. After Yang disposed of his weapon, Adam is overwhelmed after she and Blake manage to impale him.
Upon being confronted by Sun in "Haven's Fate", Adam wonders if he was forced by Blake to fight for her in an attempt to intimidate him. Only for Sun to point out Adam's goons surrendering, despite the latter's claims he has powerful friends. During their brief battle, Adam is struck in the face by Sun. He then escapes to lure Sun and Blake to pick them off but to no avail.
In his message to the Albain brothers in "Necessary Sacrifice", Adam shouts that the Belladonna name has brought him nothing but grief. He then orders the assassination of Ghira and Kali along with their daughter's capture. His assassination plan is ultimately thwarted by Blake and Sun, with Ilia switching sides and Corsac being arrested after Fennec's death.
In the "Volume 6 Adam Character Short", Adam saves the former High Leader, Ghira, from being killed by a human assailant.