Once you have performed Arito's task you can dig for the secret entrance, similar to the way you would look for a tomb. You may pass through the back door to enter the cave, without sacrificing a scimitar. (this is after going back to muhad).
There are two entrances, the first official entrance is in the mountains between ank and dara, just east of the passage to Darashia, here.
<spoiler>To access this entrance you need to start Arito's Task. After that you'll need to place a scimitar on that crack, and use a vial of water 2sqm east from the crack, and a secret entrance will appear.</spoiler>
The second "secret" entrance is near the first entrance, on the desert. You'll need a shovel to open the hidden hole. Inside there is a door that can only be opened if you have completed Arito's task. So completing it is necessary to use this entrance. The hole can be found around here NOTE: To open the hole you might have to dig multiple times on the correct sand tile. Archivo:Nomads Entrance2.png