On this page of the Sons of the Forest guide, you will find the location of the cross. You will also find out what it is for.
Where to find the cross?
The cross can be found in several places on the map. However, you must keep in mind that this is a unique weapon, so if you pick it up once, it will disappear from other locations.
At the moment there are two places where you can get the cross. The first one is a cave where you also find a rope gun. It is located at the very beginning of the system - it is highlighted in such a way that it casts a shadow on the wall.
The second place where the cross may lie is the bunker on the beach in the eastern part of the map. It lies at the very end of the location - in the apartment where the passage to the final section is located. It is on the dresser.
What is the cross for?
The cross is a form of weapon that allows you to fight Demons. This is a unique type of enemy that appears only in the final sequence - the cave that you can get to using the golden armor. If you point the cross at this creature, it will start burning. It is one of the most effective methods of fighting them.
However, you must bear in mind that the cross will not work on other hostile creatures inhabiting the island. In this case, you have to use conventional weapons.