Question: Mullah Mohammad Rabbani Akhund, was one of the main leaders of the Taliban movement, he was second in power only to which supreme leader?

full_context: Document 1: Hibatullah Akhundzada: Mawlawi Hibatullah Akhundzada (Pashto: هبت الله اخونزاده‎ ; Arabic: هيبة الله أخوند زاده‎ ‎ Haibatullāh Aḫūnd Zādah; born 1961) is the Emir (leader) of the Taliban, an Islamic fundamentalist political movement in Afghanistan.
Document 2: Abu Umar al-Tunisi: Tariq bin al-Tahar bin al-Falih al-'Awni al-Harzi (3 May 1982 – 16 June 2015), known as Abu Umar al-Tunisi, was a Tunisian man and senior leader of the Islamic State.
Document 3: Hassan al-Banna: Sheikh Hassan Ahmed Abdel Rahman Muhammed al-Banna (Arabic: حسن أحمد عبد الرحمن محمد البنا‎ ‎ ; 14 October 1906 – 12 February 1949), known as Hassan al-Banna, was an Egyptian schoolteacher and imam, best known for founding the Muslim Brotherhood, one of the largest and most influential Islamic revivalist organizations.
Document 4: Taliban: The Taliban (Pashto: ‎ "ṭālibān " "students"), alternatively spelled Taleban, which refers to itself as the Islamic Emirate of Afghanistan (IEA), is a Sunni Islamic fundamentalist political movement in Afghanistan currently waging war (an insurgency, or jihad) within that country.
Document 5: Akhtar Mansour: Mullah Akhtar Mohammad Mansour (Pashto: اختر محمد منصور‎ ; or ;  1968 21 May 2016) was the Emir (leader) of the Taliban, an Islamic fundamentalist political movement in Afghanistan, from 29 July 2015 to 21 May 2016.
Document 6: Abdul Rahim Ghafoorzai: Abdul Rahim Ghafoorzai (d. August 21, 1997) was a politician and diplomat of Afghanistan. He was an ethnic Pashtun, a member of the Barakzai Mohammadzai tribe. During the 1970s he entered the Afghan foreign service. He was sent to the United States to represent the political administration supported by the Soviet Union. As the Ambassador to the UN, Mr. Ghafoorzai thought it his duty to call on the global partners to denounce the Soviet invasion in 1979. From then until 1992, he worked as a representative official to trigger international support against the regime that the Soviets had set up in Afghanistan. When the communist government fell in 1992, Ghafoorzai acted as an intermediary to unite the factions of Afghanistan. He worked in the United Nations until 1995, and then became deputy foreign minister. He became foreign minister in July 1996. in September 1996 the government troops withdrew from Kabul and the Taliban captured Afghanistan's capital, Kabul, The International community did not recognize the Taliban as Afghanistan legitimate government except Pakistan, United Arab Emirates and Saudi Arabia, the Islamic State of Afghanistan government established the new cabinet in Mazar e Sharif in the north of Afghanistan, meanwhile the Afghanistan Embassies and the Permanent Mission of Afghanistan to the United Nations was in control of Islamic State of Afghanistan as legitimate representative of Afghanistan. Ghafoorzai continued as Afghanistan Foreign Minister until August 11, 1997, just 10 days before his death, he was appointed prime minister of the Islamic State of Afghanistan government. He was killed in a plane crash in Bamyan Province when he was going to negotiate to form his cabinet with their allies.
Document 7: Khairullah Khairkhwa: Khirullah Said Wali Khairkhwa is a Taliban official and former governor of Herat. He was held in the United States Guantanamo Bay detainment camp in Cuba. He was released in late May 2014 in a prisoner exchange that involved Bowe Bergdahl and the Taliban five. Press reports have referred to him as ""Mullah"" and ""Maulavi"", two different honorifics for referring to senior Muslim clerics.
Document 8: Abu Abdullah al-Shafi'i: Abu Abdullah al Shafi'i (real name Wirya Salih) was the leader of the Jund al Islam and the Ansar Al Sunna from early 2003 to 2010. He is a Kurdish veteran of jihad in Afghanistan and Chechnya. On 3 May 2010, he was captured along with seven others and is being held in Baghdad Central Prison.
Document 9: Mohammad Yaqoob: Mullah Mohammad Yaqoob or Mullah Yaqoob (Arabic/Pashto: ملا محمد يعقوب) is the eldest son of Mullah Mohammed Omar, the Afghan mujahideen commander, founder of the Taliban and the former Emir (Supreme Leader) of the Islamic Emirate of Afghanistan. He was born in 1990.
Document 10: Abdul Ghani Baradar: Mullah Abdul Ghani Baradar (Persian: عبدالغنی برادر; born c. 1968), also called Mullah Baradar Akhund or Mullah Brother, is a co-founder of the Taliban movement in Afghanistan. He was the deputy of Mullah Mohammed Omar. Baradar was captured in Pakistan by a team of Inter-Services Intelligence (ISI) and Central Intelligence Agency (CIA) in February 2010 and was released on 21 September 2013.
Document 11: Mohammed Omar: Mullah Mohammed Omar (Pashto: ملا محمد عمر‎ , "Mullā Muḥammad ‘Umar"; c. 1960 – 23 April 2013), widely known as Mullah Omar, was the supreme commander and spiritual leader of the Taliban. Under the title "Head of the Supreme Council," He was Afghanistan's head of state from 1996 to late 2001. Omar died in 2013 of natural causes and was succeeded by Mullah Akhtar Mansour.
Document 12: Abdul Madzhid (Dagestan rebel): Ilgar Mollachiev, better known as Emir Abdul Madzhid (Majid), was the militant leader of the Shariat Jamaat of the Caucasian Front in the Second Chechen War, in the volatile southern Russian republic of Dagestan. He was the deputy of Rappani Khalilov until Khalilov's death in September 2007. He was then appointed the new leader of the Shariat Jamaat by the orders of Dokka Umarov. His nationality was Tsakhur.
Document 13: Mohammad Rabbani: Mullah Mohammad Rabbani Akhund (1955–15 April 2001) was one of the main leaders of the Taliban movement. He was second in power only to the supreme leader, Mullah Mohammed Omar, in the Taliban hierarchy.
Document 14: Mohammad Ghous: Mullah Mohammad Ghous (born 1961?) was among the leadership of the Taliban which ruled Afghanistan from 1996 to 2001. He served as foreign minister of Afghanistan from September 1996, when the Taliban captured Kabul until June 1997, when he and some other Taliban leaders were kidnapped by opposition forces at Mazar-i-Sharif in the northern part of the country. Ghous reportedly escaped in September 1997 when the Taliban captured that city, but he was not reappointed as foreign minister, and his whereabouts since then are not well known.
Document 15: Andar (Pashtun tribe): The Andar are a Ghilji Pashtun sub-tribe. The Andar occupy nearly the whole of the extensive district of Shalgar south of Ghazni The Andar had been known for their skill and usage of large karez (underground irrigation systems). More concentrated in Ghazni Province, they have also a significant presence in Paktia. During the 19th century they joined in the Ghilji revolt and many were summarily sent into internal exile. Somewhat inexplicably, they allied themselves for a time with the Harakat-i Islami, originally a Shia faction, during the anti-Soviet campaign. In fact, there were two Mujaheddin parties named Harakat-i Islami Afghanistan, while one was a Shi'ite faction, the other and far more significant party was originally a 'united front' of mainly Hezb-i Islami and Jamiat-i Islami, that collapsed after only a few months, leaving behind a significant party that was in many ways a precursor to the present day Taliban movement. A majority of the Andar tribe were affiliated with this 'Harakt-i Islami' and it is notable that the leader of this united front and later party, Mawlawi Mohammad Nabi Mohammadi was Andar by tribe. Similarly, the senior Mawlawi Mansoor was Andar too. Mansoor's son Saifurrahman Mansoor was later an important figure and military leader in the Taliban movement.
ground_truth: Mullah Mohammed Omar