Shayegan, M. Rahim. 2012. Aspects of History and Epic in Ancient Iran: From Gaumāta to Wahnām. Hellenic Studies Series 52. Washington, DC: Center for Hellenic Studies. http://nrs.harvard.edu/urn-3:hul.ebook:CHS_ShayeganM.Aspects_of_History_and_Epic_in_Ancient_Iran.2012.
Chapter 4. The Evil Brothers in the Iranian Tradition
The Legend of the Indo-European Twins
The story of Hārūt and Mārūt from Sūrābādī’s tafsīr (1091 CE):
The Twin Brothers in Creation Myths
manahicā vacahicā # š́iiaoθanōi hī vahiiō akəmcā
åscā hudåŋhō # ərəš vīš́iiātā nōit̰ duždåŋhō
The twin thoughts and speeches—they are twin actions: a good and a bad one.
And between those two those who give good gifts [or: establish good things] have discriminated rightly, not those who give bad gifts. 
yasca spəṇtō mainiiuš yasca aŋrō
the Life-Giving Spirit and the Evil one.
azəm yō ahurō mazdå
airiianəm vaējō vaŋhuiiå dāitiiaiiå
āat̰ ahe paitiiārəm frākərəṇtat̰
aŋrō mainiiuš pouru.mahrkō
ažimca yim raoiδitəm ziiąmca daēuuō.dātəm
I, Ahura Mazdā, the Aryan Expanse of the Good (river) Dāitiiā  (the Lawful)
Then the Evil Spirit full of destruction brought forth as its antagonist
a dragon, the red, and the winter made by the daēvas.
ud padisāy ēn saxwan rasēnd ō wanyūdīh
and on account of this saying they shall come to ruin.
It is also evident in a passage of the Warštmānsr nask  —serving as an exegesis on the Gathic strophe of the twin mainiius—that disapprovingly comments on their being brothers:
And the Bundahišn reports:
Although the separation of opposite principles maintained the perception of Ōhrmazd’s essential purity, as he was not responsible for begetting the Evil Spirit, it certainly must have been perceived as a limitation to Ōhrmazd’s omni-potence at some point in the long journey of Zoroastrian thought. 
The Two Brothers in the Iranian Epic Traditions
The Šāhnāme: Fereydōn and His Brothers Katāyōn and Barmāye (Barmāyōn)
az-o har dō āzāde mehtar be sāl
yekī būd az ēšān Katāyōn-aš nām
degar nām Barmāye-ye šādkām
the two highborn ones were older than him in years.
One of them was called Katāyōn,
and the name of the other (was) the gay Barmāye.
tabah kardan-aš rā bēyārāstand
be pāyān-e koh šāh xofte be nāz
šode yek zamān az šab-e dēryāz
yekī sang būd az bar-e borz kōh
barādar-aš har dō nehān az gorōh
davīdand bar kōh o kandand sang
bedān tā bekōbad sar-aš bē-derang
vo-z-ān kōh γalṭān ān forō-gāštand
mar-ān xofte rā košte pendāštand
be farmān-e yazdān sar-e xofte-mard
xorōsīdan-e sang bīdār kard
be afsōn hamān sang bar ǰāy-e xvēš
bebast o naǰonbīd ān sang bēš
and planned for his demise.
The king was peacefully asleep in the mountain’s foothills,
some time had passed from the long night.
There was a stone on top of that tall mountain,
his two brothers moved away in secret from the group,
they ran towards the mountain and detached the stone,
so that it may crush his [Fereydōn’s] head at once,
rolling it, they threw it down from that mountain (top),
they were (already) deeming the sleeping one killed,
(but) by order of the gods the clamor of the stone
awakened the sleeping man.
Through magic he [Fereydōn] bound the stone in its place,
And no further did that stone move.
The Dārābnāme: Dārāb and the Brothers Māhyār and ǰānōsyār
The Samak-e ʿAyyār: Xōršīd Šāh and the Brothers Alīyān and Alyīār
Bigthan and Teresh in the Book of Esther 2:21–22
The reason for this anger has been variously explained as a result of Queen Vašti—among whose followers Bigthan and Tereš  may have been—being deposed by Xerxes and replaced with Esther, jealousy, and more. 
āat̰pasca θrišāmrūta vaca
ime vaca framruua vārəθraγne baēšaziia
paiti.pərərne Nåŋhaiθīm daēum …
And after the words which are said three times,
say forth these healing words, rich in obstruction-smashing strength:
I prevail/fight against [the daēuua] Indra,
I prevail/fight against [the daēuua] Sauruua,
I prevail/fight against the daēuua Nåŋhaiθiia …
On the meaning of pərən- “overcome; fight (against),” see Kellens 1995:33, and Sims-Williams 1989:258, with reference to Khotanese purr- “to overcome.”
Solomon disbelieved not,
but the Satans disbelieved, teaching
the people sorcery, and that which was sent down
upon Babylon’s two angels, Harut and Marut;
they taught not any man, without they said,
“We are but a temptation; do not disbelieve.”
From them they learned how they might divide
a man and his wife, yet they did not hurt
any man thereby, save by the leave of God,
and they learned what hurt them, and did not
profit them, knowing well that who so buys it
shall have no share in the world to come;
evil then was that they sold themselves for,
if they had but known.
yə̄ vå mazdā ahurā # +pairijasāi vohū manaŋhā
maibiiō dāuuōi ahuuå # astuuatascā hiiat̰cā manaŋhō
(I) who embrace you with the Good Thought, o Ahura Mazdā (so that) you give me the rewards/boons of the two states of existence (ahu-), the bony one and that of thought …
yat̰ titarat̰ aŋrō mainiiuš
dāhīm aṣ̌ahe vaŋhə̄uš
vohuca manō ātaršca
tå hē tauruuaiiatəm t̰baēšå
aŋrahe mainiiə̄uš druuatō …
When Aŋra Mainiiu crossed over … of good Order, the Good Thought and Fire came down in-between. Those two overcame his aggressions, those of the deceitful Aŋra Mainiiu … [ back ] On this passage, see Skjærvø forthcoming: ch. 8.4; and Skjærvø 2011b:341. On the meaning of the injunctive verbal form titarat̰ (~ tar “hinübergelangen über; cross over”), see also Skjærvø 1995 :268n12. Also Kellens 2003:237.
[az buni]št ī Ahremen
[ud nē A]hremen az buništ
From the origin of Ahreman
and Ahreman is not from the origin
of Ōhrmazd. (Sunderman 1981:24.3.ii, vv. 9–11)