Angel #8 spoilers coming! The Slayerverse's various universes' ability to contextualise the more formally canonical versions of both Buffy the Vampire Slayer and Angel is one of its benefits. For those who don't know, the Slayerverse is essentially the multiverse as it pertains to Buffy the Vampire Slayer, with several realities revolving around Buffy and the Scooby Gang. These several alternate universes alter the established canon to depict scenarios like Willow as the Vampire Slayer, an older Buffy living in a post-apocalyptic future, or even Buffy as a zombie.
With the exception of routinely driving a stake through their chest, of course, Buffy Summers is no stranger to the dead. Buffy is killed by The Master in the season finale of the first season of the programme, only to be revived moments later. More tragically, Buffy would pass away once more in Season 5, giving her life to save her sister, only to be revived in the first episodes of the season after. One may argue that both of these deaths were heroic in some way because she died while on duty battling Big Bads. Buffy experiences a death that is both more lasting and less remarkable in the other universe that BOOM! Studios' Angel comic series is set in.
Related: There is also a multiverse for Buffy the Vampire Slayer
In this universe, Wesley serves as Fred's Watcher, and she largely lives Buffy's canon life—to the extent where she even dated Riley while in college. In Angel #8, by Christopher Cantwell and Daniel Bayliss, it is revealed that in this version of events, Buffy was killed by a vampire just a few weeks after finding out she was a Slayer. She is revived to battle on Angel's team in this issue, which is set years after the event. Most intriguingly, despite not having Buffy in his life at the time, Angel still manages to run into the Scooby Gang. It appears that Willow and Tara lead a Dungeons & Dragons group in Sunnyvale that Angel himself attends covertly every Thursday.
The fact that Buffy is still a unifying force that ties her friends together is a testament to the level of significance she maintains inside the Slayer's multiverse as a whole. Buffy's presence, at least in this universe, is barely a minor footnote in the Slayer universe, let alone the universe as a whole. Buffy is just a Slayer for a short time, and she isn't even that competent to keep the position for more than a few weeks.
Even so, when the fate of the world is in jeopardy, she still manages to dominate the narrative. Before this issue, Angel had never even heard of Buffy Summers. However, she is significant enough to join his squad and serve as a bridge between him, Tara, Willow, and other frequent Scooby allies as well as Buffy Summers. Although Buffy the Vampire Slayer is the key that unites friends like Angel under one roof in the Slayerverse, her sister Dawn may actually be The Key.