A massive series-long mystery has been unlocked.

Warning: This article contains spoilers fromStranger Thingsseason 4, Volume 2.

Everything onStranger Thingsleads back to One, a.k.a.

Stranger Things

Vecna (Jamie Campbell Bower) has a connection to the very beginning of ‘Stranger Things.'.Netflix

Henry Creel, a.k.a.

Vecna (Jamie Campbell Bower).

Vecna is the Mind Flayer.

Stranger Things

The Mind Flayer as seen terrorizing Hawkins in ‘Stranger Things’ season 2.netflix

The Mind Flayer is Vecna.

After his first battle with Eleven, One found himself in the Upside Down.

He became an “explorer,” he says and he discovered “something that would change everything.”

We then see One use his powers to mold the cloud into the spindly shape of the Mind Flayer.

Vecna did say he had a fondness for spiders, particularly Black Widows.

It was really One/Henry/Vecna this whole time.

We learn from the first episode of Vol.

Vecna is also still alive by the time the end credits roll.

When Will steps foot back in Hawkins, those strange feelings start to creep back.

Stranger Thingsseason 4 is now streaming in its entirety on Netflix.