How to unlock the secret boss in Loop Hero: How to get the true ending

There are four main bosses in Loop Hero, allowing you to see the standard ending. But there is also a secret one that unlocks the true ending...

To fight the four Demiurges, first complete the first two chapters by defeating the second boss, the Priestess, at least once. After all this, go to any cycle, taking with you certain road maps with a range of one cell. Find a straight line and place along it top and bottom (or left and right if it is vertical) 4 cards that will affect each other:

• For example, first create a grove on the road and place a Bloodgrove on the left. Destroy the Blood Grove with Oblivion, allowing it to turn into Hungry Grove.
• Then create a vampire mansion and a road lantern on the sides of the bloody grove.
• Opposite the bloody grove, on the other side of the road, build a bookstore.
• Place chronocrystals above the bookstore, and below - the battlefield.

These are six tiles that affect one cell in the center, between them. And on this cell of the road, where b?la ordinary grove, blue sparks will appear. Use Oblivion on these sparks, resulting in a portal. The next time your character passes through it, you will be transported to the Demiurge dimension.