Negotiations were going on with Hindi actor Amitabh Bachchan for a role. However, close to filming it was reported Tamil actor Sathyaraj had replaced Bachchan. It was for the role of Manikyan's grandfather, for which Hindi actor Manoj Joshi was ultimately cast. Writer Harikrishnan said, Bachchan had indeed agreed to work in the film, but was unable to join due to personal reasons. Since the film would have been delayed if they waited for Bachchan, they move on to other actors. In June, a casting call was released seeking children and teenagers for playing the younger versions of Mohanlal, Warrier and Raj. It also invited youngsters for other undisclosed roles. In September, Aneesh G. Menon confirmed he is part of the cast. In November, Narain confirmed he is part of the cast and would join the film in its final schedule, which will shoot Odiyan Manikyan's younger age. He plays the husband of Prabha and his scenes are with Mohanlal, Raj and Warrier. From the teaser trailer released in December, more of the cast was revealed confirming Kailash, Sana Althaf, and Sreejaya Nair. Sana plays Warrier's sister and Kailash's wife in the film. She said it was a difficult role to portray. The character has less screen time but is important in the script. Her character has transition from a young girl to an aged woman. Including Sana, many of the artists were prepared through a week long acting workshop. Atul Mongia served as the acting workshop director. Filming Principal photography began on 25 August 2017 in Varanasi, Uttar Pradesh. Mohanlal joined the film three days later. Some scenes were shot at the Assi Ghat with Mohanlal. Underwater action scenes were filmed in the Ganges River. In Varanasi, the film was extensively shot at the Havelis, the lanes, and the Ghats. Sreejaya Nair was also part of this schedule. In the film, Odiyan Manikyan spent 15 years in the sacred lands of Varanasi before returning to his native village, Thenkurissi. This period of his life, his older age, was filmed there. After completing, the crew left Varanasi by the end of the month and remaining was the scenes in Thenkurissi. Since the film wanted a period setting, the modern-day Thenkurissi was unsuitable for filming. Hence, the village was recreated in a 20-acre land in Mucheeri, Palakkad district. The second schedule in Palakkad was scheduled to begin on 6 September. Raj