Merlin Trial is a type of open world puzzle that you can find everywhere in Hogwarts Legacy.
There’s one Merlin Trial at South Feldcroft, which is at the southwest part of the map.
Here’s a guide on the South Feldcroft Merlin Trial in Hogwarts Legacy.
The exact location is shown in the map below.
How to solve the South Feldcroft Merlin Trial
To begin, use Mallowsweet on the swirl on the ground.
Then, use Revelio and you should see five rock formations around the area.
All you need to do is to destroy all five rock formations. You can use a spell like Bombardo or Confringo.
After destroying them all, the Merlin Trial ends.
Hogwarts Legacy: Jackdaw’s Rest Merlin Trial Guide