- "Shanshu has roots in so many different languages. The most ancient source is the Proto-Bantu and they consider life and death the same thing, part of a cycle — only a thing that's not alive never dies. It says that you get to live until you die. It says the vampire with a soul, once he fulfills his destiny, will shanshu. Become human. It's his reward."
- ―Wesley Wyndam-Pryce[src]
The Shanshu Prophecy was a prophecy contained within the Scrolls of Aberjian and, as translated by Wesley Wyndam-Pryce, foresaw the coming of a vampire with a soul that would play a pivotal role in the apocalypse. As a reward, he would be restored into a mortal human being. Translated from its oldest root, the word "shanshu" meant both to live and to die, thus meaning that Angel would "live to die" by becoming human and eventually dying a mortal death. It was assumed that Angel's role will be one of good, but many people pointed out that the prophecy did not specifically say so.
The prophecy became Angel's driving motivation. As the prophecy did not refer to a particular apocalypse, Angel determined that redemption rather than a scorecard of good deeds was the key to Shanshu. He maintained a constant battle against evil, rather than just try to amass a demonic body-count. However, Angel's faith in his role wavered when he took on a more corporate, bureaucratic approach to fighting evil. He took control of the Los Angeles branch of Wolfram & Hart and felt disconnected from his mission.
For years it was assumed that the prophecy was about Angel, even after Spike became the second vampire to have a soul, because Spike was not a Champion. However, after Spike died to save the world, becoming a Champion in the process, the subject of the prophecy came into question once Spike is re-corporealized. Angel's old foe, Lindsey McDonald, briefly attempted to manipulate events to set Spike up as the true champion to discredit Angel. However, Spike's main interest in the Shanshu was generally a continuation of his rivalry with Angel rather than a specific desire to become human himself.
This conflict came to a head when Spike was restored to corporeal status. Lindsey faked an addendum to the prophecy with the aid of renegade ex-Watcher Rutherford Sirk during a series of apparent distortions in reality caused by the existence of two "candidates" to the prophecy. He pitted Angel and Spike against each other to drink from the Cup of Perpetual Torment in order for one of them to be confirmed as the true subject of the prophecy. Although both Angel and Spike survive the fight and the Cup is exposed as a fake, Angel began to question his status as the vampire Champion when Spike defeated him for the first time in their long history. Despite Lindsey's efforts to discredit Angel and establish Spike as a Champion, his scheme was eventually defeated. Angel and Spike went on to become an effective, if argumentative, team until their final suicidal confrontation with the Circle of the Black Thorn.
- Spike: "What do you think all this means for that Shanshu boogaboo? If we make it through this, does one of us get to be a real boy?"
- Angel: "Who are you kiddin'? We're not gonna make it through."
- — Angel and Spike discuss the Shanshu Prophecy[src]
Unknown to Spike, however, Angel signed away his rights to the Shanshu Prophecy in order to infiltrate the Circle. The Circle members wanted to ensure Angel had genuinely forsaken his old life as a champion. Angel took advantage of the Circle's inability to comprehend the idea that he would do good for the sake of it rather than for a reward. As Angel informed Marcus Hamilton during their confrontation after he rescinded his role in the Prophecy, "people who don't care about anything ... will never understand the people who do."
During the Fall of Los Angeles, Angel was transformed into a human by the Senior Partners to hinder him. Angel dismisses the idea that this was the Shanshu prophecy fulfilled. Later, Wolfram & Hart revealed through Wesley that they never filed his signature before the firm was destroyed and the Shanshu was still his and could still be fulfilled. Wesley stated that the prophecy had always concerned Angel alone. While Angel was near death after being badly beaten by the then-vampire Charles Gunn, Gunn speculated that he could be the vampire to Shanshu as the vampire with soul rather than the vampire with a soul. Angel then received a vision of the final apocalyptic battle.
The vision revealed that Angel's role in the Shanshu would be one of evil. It showed him as a vampire standing in a field of dead bodies. Angel chose to resign himself to death rather than let these events come to pass, but Connor and Cordelia Chase assured him that this future would not happen in any event, as Angel would never allow himself to become the man that he saw in the vision. Angel vowed to continue trying to help others even after his return from Hell and the restoration of his vampire status.
For a time, Spike argued that he might be the "true" candidate of the prophecy, with Angel being merely a "smokescreen" to draw attention away from him. Subsequent discoveries forced him to recognize that he had been trying to hang on to Angel's glory rather than finding his own path, prompting him to abandon all thought of the Shanshu Prophecy and depart Los Angeles for Las Vegas to form his own team and find himself on his own without trying to compare himself to Angel.
Angel, in his guise as Twilight, demonstrated a significant increase in strength and power. He was also able to have sex with Buffy Summers while flying during the daytime without losing his soul or burning up. This was apparently a "superior" reward to the Shanshu, with the higher power that informed Angel of his recent upgrade dismissing the Shanshu as nothing compared to what he had become.
However, given that the final resolution of the Twilight crisis resulted in Angel apparently defying his "destiny" to create a new world, Angel himself doubted that he was entitled to the Shanshu anymore. He told Faith that fulfilling the Shanshu Prophecy was "out of the question" and that all he had to look forward to was a stake to the heart. However, Faith was certain that, with the end of magic having effectively prevented any more Hellmouth-spawning apocalypses, Angel had indeed earned the Shanshu.