I remember this movie from when I was younger.   I’ve no idea on the release or when exactly I watched it but it had to of been in the mid to late 80’s.

Starts off with the inhabitants of a village all frantic to pack and flee as quickly as they can.   Every so many years this cult would return and bring evil with them.

A young girls falls asleep or gets lost while playing with her friends in some tower or water mill type structure.  Her father stays behind searching for her.

Two male backpackers traveling across the region wander into the village as the people are fleeing.  They disbelieve the legends told to them or could have not understood the meanings.

The cult arrives after the dark falls and begins capturing villagers and hunting down anyone in the area.  Victims caught were hung on a cross and placed before a creature.  It would open its two arms wider revealing a third arm with three fingers extending from its chest.  When placed on the chest of the victim it would burn/brand them leaving a three fingered mark.  They would then become devoted followers.

The father ends up being captured later on and he is branded.

The two hikers are running down a stone staircase from some cultists when one of them falls.  With an injured leg he can no longer run so his friend pulls him aside and keeps running to lure away the cultists.

I’ve no idea who stars in it,   was before my mind payed attention to those parts of the movie.  I’m sure there is more that happens but this bit is what my mind remembers the most.