I've just found this interesting theory (copy/pasted):

Yasha-sama is facing something...or someone...beyond our imagination (THEORY)



In the 1st chapter we've got a fast introduction of Yasha-sama, Great Master and probably founder of the Kongo-Yasha Style.

She could also be a divine figure of the Buddhist Cosmology:

Yasha - demon gods from Buddhist cosmology

The 1st impression about Yasha was, for most of us, that she is a Top Tier Samurai or, more precisely, the Grand Master of the Kong-Yasha Style.

However in the Japanese and Buddhist folklore and cosmology (that Kishi loves and has already used in Naruto/Boruto...also in Samurai 8, with Fudo Myoo, as you know) Yasha is something far higher than a "common" Samurai.

If we take into consideration the Buddhist cosmology:

" Yasha are a race of powerful, high ranking nature spirits which appear in Buddhist cosmology. They are a type of kijin, or demon god–both worshiped as benevolent gods and feared as wrathful demons. They are fearsome warriors, and serve as guardians of the treasures of the earth. They have varied forms, but generally are humanoid in appearance.

BEHAVIOR:Yasha are one of the members of the the Eight Legions–eight supernatural races who listened to the sermons of Shaka Nyōrai and converted to Buddhism. Along with the Ten, Tatsu, Kendatsuba, Ashura, Karura, Kinnara, and Magoraka, they serve as guardians of the Buddhist teachings.

Yasha serve Buddhism in a number of ways. Most importantly, theTwelve Heavenly Generals(the twelve most fearsome yasha), serve as the personal bodyguards of Yakushi Nyōrai, the buddha of medicine. They wage war on sickness and fight the enemies of Buddhism. They are also important in astrology–as there are twelve of them."

Ashura and Karura of the Eight Legions

There are several connection between S8 Yasha and Buddhism Yasha. The most important is the Souls Wheel-like thing behind their heads...and the diadem.

But there's also another important figure that Kishimoto has stated/introduced in the last chapter (n.7)...someone named Ususama/Occhusma and, just like Yasha, Leader of the Ususama Style and rival (so it seems) of the Kongo-Yasha Style. Another important deity from Buddhism:

" Ususama is a Vidyaraja (wisdom king) in the Vajrayana sect of Buddhism. He is also known by various other names such asBurning Impurity Kongo*.* His full name is Great Strength Furious Diamond Ucchuṣma.

Back to the 1st chapter and The Destroyer:

In the first pages we can see her Space Holder, a huge whale, approaching an intense and extremely vast light, while speaking about his sacred duty "to keep at bay the one who brings destruction" also called by the fanbase "The Destroyer".At the beginning i thought it was just a sun or a dying star...but thanks to the last chapters i changed my mind.

As we can see there are many distant pyramid-like planets and, thanks to the recent chapters, we know that some Galactic Quadrant are named with the shape of these real proper planets.

The real deal is all in this pic.

I think that's not a sun nor a dying star at all...in my opinion that's a hella huge Samurai Soul. Enough huge to be comparable to a star.You can notice how similar it is with the Soul that Daruma and the other Samurai uses to create a Soul Blade.

You can imagine how big someone must be in order to use it as a Soul Sword. And the most impressive thing is that Yasha-sama is facing this being all alone (or so it seems. If we take into consideration the Buddhist Cosmology she might be part of the Twelve Heavenly Generals).

And my theory is that...this being is Yama, God of Death,the "nemesis" of Fudo Myoo in the Buddhism.

. . . . . . . . . . . . . . . . . . . . . . . . . . .

----> I've found this an interesting and entertaining read.

Hope you enjoy.