Tsar Nicholas II ruled Russia from 1894 till 1917 when he abdicated following the revolution in March 1917. Nicholas II inherited Russia when it was in a very bad state, and although there were minor improvements during his reign, compared to many other countries it was very backward, perhaps then it was almost defiantly inevitable that sudden change was going to happen, however not necessarily in the form of revolution. The Tsar was in a difficult situation, but he had opportunities to end some of the problems in Russia, which after the 1905 Revolution it appeared as if he was, and it was due to his mistakes, most notably leaving Petrograd to lead the army in 1915, that the Revolution occurred, so it was definitely partly the Tsar's fault that his downfall came about.
The First World War was a very important factor in Nicholas II's downfall, in 1914 it started off well with increased public support for the Tsar, however because it was poorly organized by the Tsar the situation in Russia became worse and worse. Most importantly the army, who had supported the Tsar in the 1905 Revolution and played an important role in ensuring that revolution did not occur in 1905, were now turning against the Tsar meaning they were less and less likely to support him if another revolution broke out, and without their support Nicholas II had little power- he had always used violence to crush any opposition previously, and so would be perhaps destined to fail when faced with any opposition. The war lead to food shortages and unemployment, this would have happened whoever was in charge of Russia but due to the poor organisation these problems became worse and worse and the Tsar's downfall looked more likely. Nicholas' unpopular decision to leave Petrograd leaving the Tsarina and Rasputin in charge of the day to day running of Russia was because of the war, however it was Nicholas' fault that this decision was made and this decision was a big factor in his downfall. Overall