Question: In the Persian epic poem Amir Arsalan, what kind of weapon is Shamshir-e Zomorrodnegār?
Context: Shamshir-e Zomorrodnegār (Persian: شمشیر زمردنگار, 'the emerald-studded sword') is a sword in the Persian legend Amir Arsalan.  The witch mother of a hideous horned demon called Fulad-zereh used a charm to make his body invulnerable to all weapons except this specific sword. Fulad-zereh (Persian: فولادزره‎ ‎ Fulâd-zereh) meaning "[possessing] steel armor," is the name of a huge horned demon in the Persian story of Amir Arsalan. BĪŽAN-NAMA (Persian: بیژن نامه‎ ‎ ) is a Persian epic poem of ca. 1,900 couplets relating the adventures of the legendary hero Bīžan son of Giv.  Zabiollah Safa, an Iranian literary scholars notes that a large number verses of thies epic were taken from the Bīžan and Manīža in Ferdowsī’s Šāh-nāma.  Jalal Matini after closely postulated that the epic is mainly a copy of Ferdowsī’s story with some verses added by the author and some of Ferdowsi’s omitted. The Shahnameh, also transliterated as Shahnama (Persian: شاهنامه‎ ‎ ] , "The Book of Kings"), is a long epic poem written by the Persian poet Ferdowsi between c. 977 and 1010 CE and is the national epic of Greater Iran.  Consisting of some 50,000 "distichs" or couplets (two-line verses), the "Shahnameh" is the world's longest epic poem written by a single poet.  It tells mainly the mythical and to some extent the historical past of the Persian Empire from the creation of the world until the Islamic conquest of Persia in the 7th century.  Modern Iran, Azerbaijan, Afghanistan and the greater region influenced by the Persian culture (such as Georgia, Armenia, Turkey and Dagestan) celebrate this national epic. This is a list of episodes of the anime series "The Heroic Legend of Arslan", based on a Japanese fantasy novel series by Yoshiki Tanaka based on the Persian epic, Amir Arsalan, with original character designs by Hiromu Arakawa, divided into two seasons. The Borzu Nama (pronounced as Borzū-Nāma or Borzū-Nāme) (Persian: برزونامه‎ ‎ ) is a Persian epic poem of about 65,000 couplets recounting the exploits and adventures of the legendary hero Borzu, son of Sohrab and grandson of Rostam. Garshāspnāme (Persian: گرشاسپ‌نامه‎ ‎ ) is an epic poem by Asadi Tusi.  It has been described as one of the best epic poems in Persian literature, comparable to Shahname, by Jalal Khaleqi-e Motlaq, and the most important work of Asadi Tusi.  Asadi Tusi completed the poem in 1066 AD and dedicated it to a certain "Abū Dolaf", the ruler of "Nakjavān" (nothing is known about him).  The poem is also translated to other languages such as French and German.  It seems that Asadi Tusi wrote this poem based on a written source.  Like Shahname, it contains few Arabic loan-words and consists of some 9,000 verses.  The main hero of this epic poem is Garshasp, the son of Etret, and grandson of Šam.  The poem begins with the story of Jamshid and Zahhak.  Jamshid is overthrown by Zahhak and flees to Zabolistan.  In Zabolistan, Jamshid falls in love with an unnamed daughter of Kurang, the king of Zabolistan, and she bore a child for Jamshid, named Tur (not to be confused with Tur, the son of Freydun).  Jamshid flees again to China.  Garshasp is actually the grandson of Tur's grandson. Amir Arsalan-e Namdar (Persian: امیر ارسلان نامدار‎ ‎ ) is a popular Persian epic, which was told to Nasser al-Din Shah Qajar, the Qajar Shah of Persia in the 19th century (though the Persian legend itself is much older), by a storyteller named "Mohammad Ali Naqib al-Mamalek" (Persian: میرزا محمدعلی نقیب‌الممالک‎ ‎ ).  Mohammad never transcribed the poem himself, but the daughter of the Shah—who also loved the story—eventually transcribed it and preserved it for history. Kush-Nama (Persian: کوش نامه‎ ‎ ), is a Persian epic poem and part of a mythical history of Iran written by Ḥakim Iranshān (or Irānshāh) b. Abu'l-Khay between the years 501-04/1108-11. Amir Arsalan Motahari (Persian: امیرارسلان مطهری‎ ‎ ); is an Iranian football striker who currently plays for Iranian football club Pars Jonoubi in the Persian Gulf Pro League.
Answer: a sword