Main

• Priyanka Kumar as Vennila Surya – Varadharajan and Vasuki's younger daughter; Sowmya and Vishnu's sister; Surya's student turned wife. (2021–2023)
• Darshan K. Raju / Swaminathan Anantharaman as Surya Mahadevan – Sharadha and Mahadevan's son; Meenakshi and Shivanantham's nephew/foster son; Abhi and Anandhi's cousin; Madhuvarshini's ex-fiancé; Vennila's economic professor turned husband (2021) / (2021–2023)^[10][11]
• Malavika Avinash / Jyothi Rai / Harsha Nair as Sharadha Mahadevan – Mahadevan's wife; Surya's mother; Vennila's mentor. (2021) / (2021–2023) / (2023)

Supporting

• Veena Venkatesh / Sujatha Panju as Meenakshi Shivanantham – Shivanantham's wife; Surya's aunt/foster mother. (2021; 2023) / (2021–2023)
• Tarun Master as Shivanantham – Mahadevan and Vishwanathan's brother; Meenakshi's husband; Surya's uncle/foster father.
• Bhanu Prakash as Mahadevan – Shivanantham and Vishwanathan's brother; Sharadha's husband; Surya's father.
• Akshitha Ashok as Abhinaya "Abhi" Vishwanathan – Bhanumathi and Vishwanathan's elder daughter; Anandhi's twin sister; Surya's cousin
• Preetha Reddy as Anandhi Vishwanathan – Bhanumathi and Vishwanathan's younger daughter; Abhi's twin sister; Surya's cousin.
• Aarthi Ramkumar^[12] as Bhanumathi Vishwanathan – Vishwanathan's wife; Abhi and Anandhi's mother.
• Raj Khanna as Vishwanathan – Shivanantham and Mahadevan's brother; Bhanumathi's husband; Abhi and Anandhi's father.
• Sridevi Ashok as Shyamala – Meenakshi and Shivanantham's daughter-in-law.
• Reshmaa as Sowmya Madhavan – Varadharajan and Vasuki's elder daughter; Vishnu and Vennila's sister; Madhavan's wife. (Dead)
• Maanas Chavali as Madhavan – Maragathavalli's son; Sowmya's abusive husband and murderer.
• Padmini as Vasuki Varatharajan – Varatharajan's wife; Sowmya, Vishnu and Vennila's mother.
• Nalinikanth as Varatharajan – Vasuki's husband; Sowmya, Vishnu and Vennila's father.
• P. R. Varalakshmi as Varatharajan's mother; Sowmya, Vishnu and Venneila's grandmother.
• Shammi as Maragathavalli – Madhavan's mother
• Shyam Sundar as Madhavan's father
• Dayana as Roopa – Vennila's college friend
• Raghavendran Puli / Chandru as Maaran – Vennila's college friend.
• Harish as Seenu – Surya's best friend
• Gana Hari as Tamizh – Vennila's college friend
• Dhilip Kumar as Akash – Vennila's college friend

Cameo appearances

• Janani Ashok Kumar as Madhuvarshini – Surya's ex-fiancé (2021)
• Ashwini Aanandita as Shivani – Surya's colleague and one-sided lover (2023)
• Vinoth Babu as Vetri - a well known rowdy who intervenes to save Vennila from Inspector Anbu (2023)

Development

At the end of 2020, Star Vijay planned an official Tamil remake of Star Jalsha's Bengali language series Mohor to be produced by Endemol Shine India.^[13]

Casting

Actor Darshan K. Raju was cast in the male lead role as Surya Mahadevan, who is a professor. In October 2021, Darshan K. Raju opted out from the show and was to replaced by Swaminathan Anantharaman.^[14] As per reports, "Surya Darshan is leaving the show to pursue a career in the film industry."^[15] Priyanka Kumar was cast as Vennila, who aspires to be an educationist. Actress Malavika Avinash was selected to portray the role of Sharadha Mahadevan (Surya's mother) who played an important role, but in September 2021 she quit the series. Actress Jyothi Rai was cast to play the role of Sharadha Mahadevan.^[16] However, she also left resulting in Harsha Nair to play the role.

Veena Venkatesh was cast Main Antagonist as Meenakshi Shivanantham (Surya's aunt and foster mother). However, they had to replace her role. because she tested positive for Covid-19.^[17][18] Sridevi Ashok was cast as Shyamala.^[19]