Myriad Heavens: Not a Black Shop

A shop from the start, and everything inside is made up!

“Becoming an immortal is harder than reaching the Western Paradise.

You face restrictions everywhere? That's only because you haven't visited my shop.

Look here, excellent manuals, with a hundredfold boost in power as easy as pie.

Keep a supply of Smile-and-Fall-Down Powder, and you can become immortal in just three years.

A physique tailor-made for you, so you can stand above the crowd from birth.

The System is on the left, a spiritual field on the right.

And over there are magical treasures to help you ascend in bliss!

Honest with customers of all ages, quality goods at fair prices.

If the goods aren't up to standard, we'll pay you back a hundredfold!”

(A shop that spans the myriad heavens, with worlds of every kind. P.S. Lighthearted, snarky, and dark in tone. As for how poisonous it is... probably quite.)