How could one who lives in a desolate place and unaware of Islam held responsible in the hereafter?

Actually, it is not a matter, as it is understood. It had been debated many centuries ago and raveled out. It was not mentioned as a desolate place in the world but as a desolate mountain and a man unaware of social life. Or it had been talked about alike sample.

There is a verse in Quran. The interpretation of it is, God burdens no soul except within its capacity (Al-Baqarah Surah, 2:286) That is to say, He (swt) burdens no extra; He (swt) made persons responsible within their capacity. He (swt) places a head, which that body can carry. He does not attach the planets to the seed of the atom.

Muslim scholars interpret the verse from different point of views. Islamic canon law scholars examined it from the point of canon law; Islamic theologians examined it from the point of belief. Islamic theologians argued out the issue within capacity from the reason point of view and agreed upon, A person who lives in an isolated place on earth, unaware of society is only responsible with the truths that he can comprehend with his distinct mind. When it is said distinct mind we understand a mind, which have not ever touched with a Messenger and which have not received any divine commands.

It has been delivered many opinions about the mind and its limits. Imam Maturudi who among belief imams explained it as, A human, by using his/her brain is capable of knowing his/her creator. Therefore, he/she is responsible of believing God, but not to the other belief causes and stated prayers.

Another belief imam, Imam Eshari on the other hand argues the points as, It is impossible for someone to know God and even he/she worships to a piece of rock, he/she would be among the salvated.

As it is seen, the common point that both imams agreed upon is, A person is responsible with whatever his/her capacity allows him/her under the conditions he/she is in. Undoubtly, God is the One who knows the truth best.