Springing out of the emergence of the 'Celestial Messiah' Quoia in Empyre, the third Summers brother Vulcan has been identified as the 'Celestial Avatar' according to the first few pages of next week's X-Men #10.
July 29's X-Men #10, which ties into the over-arching Empyre event, is itself an 'event' for a different reason: it's the first new issue of X-Men in four months, thanks to the COVID-19-influenced slowdown of the comic book industry.
"The Summers family has grown a Krakoan home on the moon," reads Marvel's solicitation for this issue. "Now some new neighbors have moved in."
Here's a look at the first two pages of the issue, by writer Jonathan Hickman and artist Leinil Yu.
Those "new neighbors" are Quoi and the Cotati, who landed on the famed Blue Area of the Moon in Empyre #1 and promptly began remaking it as their own - a forest. This would go against the X-Men's recent attempts to establish their own outpost there with a Krakoan habitat, to serve as the home of the Summers family.
The Summers family, of course, includes Vulcan - a.k.a. Gabriel Summers, the brother of Cyclops and Havok. He has a connection to Marvel's cosmic wing on several levels, from his powers drawing on celestial energies to being raised among the Shi'ar.
So if Vulcan is the 'Celestial Avatar' as this preview reads, who are the previous mutants with that title? Without further context into this issue it's unclear. However, both Rachel Summers (Vulcan's niece from another universe) and Apocalypse have been called the 'Celestial Avatar' before in comics, as has the unnamed, deceased Celestial whose head is now the space station Knowhere.
X-Men #10 goes on sale July 29. In addition to the primary cover by Yu, there are variants by Ryan Brown, Phil Noto, and Patrick Zircher available. Here they are: