© 2020, © 2020 The Royal Society for Asian Affairs. The Islamic State (IS) is one of the most prominent transnational terrorist jihadist organizations. In 2013 and 2014, IS was able to control large swaths of Syria and Iraq, roughly the size of Britain, and announced the establishment of what it called the “Caliphate State”. The organization was defeated militarily through a long war on the Iraqi and Syrian fronts. Many local, regional and international parties participated in this war. In October 2019, IS's leader, Abu Bakr al-Baghdadi, was killed in a US raid at his safe house in the Syrian province of Idlib. This article will discuss the reasons of the rapid expansion of the IS, analyze the sources of its strength and assess the repercussions of its military defeat and death of its leader on its ability to survive, as well as foreseeing its future. The main conclusion of the study is that the military defeat of IS and the death of its leader does not in any way mean the end of IS and its takfiri ideology at least in the medium term. The historical record of jihadist terrorist organizations confirms that many organizations were able to adapt and maintain their continuity after the death of their leaders, as was the case with al-Qaeda after the death of Osama bin Laden in 2011. Also, IS is not a centralized, hierarchical organization, but a global terrorist jihadist network, with many affiliates, sleeper cells and supporters deployed in many countries of the world. This enhances the chances of IS's continuity, even if its structure has disintegrated in both? Syria and Iraq. Moreover, the current situation in the Arab world looks worse today than it was before the Arab Spring, which provides a suitable environment for the continuation of the IS and other jihadist terrorist organizations in the region. The IS may have weakened but it will not die easily.