Legend · 3 tellings · North India, Pan-India, South India
Two origins of the discus
The Sudarshana is either Shiva's gift at Kashi after Vishnu offers his own eye in place of a missing lotus, or Vishvakarma's work from the radiance shaved off the sun.
The Ramayana says the divine architect Vishvakarma made the discus.
The Puranas add that Sanjna could not bear her husband Surya's glare, so Vishvakarma pared away part of his radiance and forged the shavings into the Sudarshana and other weapons.
With it Vishnu beheads Rahu, Krishna beheads Shishupala and hides the sun on the fourteenth day of the war, and Sati's body is cut into the pieces that become the Shakti Peethas.
The Vaishnava account makes the discus a craftsman's work. The Ramayana names Vishvakarma as its maker. The Puranas explain the material: the sun's wife Sanjna could not stand the heat of her husband, so Vishvakarma set Surya on his lathe and ground away an eighth of his brightness, and from the shavings made Vishnu's discus among other divine weapons. The Sudarshana then appears through the epics and Puranas — taking Rahu's head at the churning, Shishupala's at Yudhishthira's sacrifice, veiling the sun so Arjuna can reach Jayadratha, cutting Sati's corpse into the pieces that become the Shakta seats, and guarding King Ambarisha.
In the Shaiva telling the discus is a reward for devotion. Vishnu goes to Kashi to worship Shiva with a thousand lotuses. As he counts, one flower is found missing — Shiva has hidden it to test him. Vishnu, whose eyes the poets always liken to lotuses, plucks out one of his own eyes and lays it in the thousandth place. Shiva restores the eye and gives him the Sudarshana. The night is kept as Vaikuntha Chaturdashi, when at Kashi Vishwanath the two gods exchange each other's leaf.
What is different here:
The discus is Shiva's gift rather than Vishvakarma's forging; the chapter location (Koti Rudra 34) is unverified.
In the Tamil country the discus became a god of its own. From the thirteenth century images, texts and inscriptions of Chakrattalvar or Chakraperumal appear, and under the Nayaks the personified wheel — sixteen-armed inside a six-pointed star, with Narasimha on his back — received his own shrines and his own mantras from the Pancharatra's Ahirbudhnya Samhita.
What is different here:
Not an origin but an afterlife: the weapon as a deity with a cult, a Nayak-period development.