The divine being Mithra, more popularly known as Meher Yazad, has been very prominent since the ancient Indo-Iranian times.
Though his standing epithet is dāvār “a judge”, he has myriad other roles to perform, the main one’s being looking after the Cosmic Lights, atmosphere, rituals, contract, promise and truth.
You will find more about Mithra/Meher on number 16 under the link ‘Zoroastrian divine beings’ on this website. Number 16 because, the 16th day of the Zoroastrian calendar month is dedicated to him.
The coming Shahenshahi month is dedicated to Mithra, and Mihrangan is a big festival during this month. I have great pleasure in including the Meher Yasht, along with the Rashne Yasht and Ram Yasht in the now almost complete Shahenshahi and Kadimi English Khordeh Avestas on this site.
New additions: Meher Yasht, Rashne Yasht and Ram Yasht in the Shahenshahi and Kadimi Khordeh Avestas.