Ekō

The title is the phonetic spelling of the word "echo." Director Dinjith Ayyathan and writer Bahul Ramesh selected the name because the word "eko" carries varied meanings in multiple languages, including "first born," "reverberation," and "strength," all of which align with the film's thematic layers.

Director Dinjith Ayyathan sought actors unfamiliar to regional audiences to prevent viewers from forming preconceived notions about the characters. This led to the casting of Bollywood actor and acting coach Saurabh Sachdeva as Kuriachan and Meghalaya native Biana Momin as Mlaathi. Momin's dialogue was later dubbed by veteran artist KPAC Leela to match the character's required tone.

Trainer Jijesh S utilized specialized methods to capture the aggressive reactions required for the script. To provoke genuine irritation and movement from the dogs, the handlers used custom masks and rubber toys. Each animal was cast based on physical specializations, with different dogs designated specifically for running, jumping, or close-up snarls.

The hills of Uppukunnu/Murakettipara were heavily modified to achieve the director's desired aesthetic. Every tree visible in the immediate vicinity of the house was transported to the location and planted by the art department. Before production, the specific hillside used for the set was largely barren of the lush vegetation seen on screen.

The production team opted against using existing structures for the primary setting in Kattukkunnu. Art director Sajeesh Thamarassery oversaw the construction of a complete, functional house in Kanjar, Idukki. To ensure the structure survived the region's intense winds and mist, the crew built a reinforced foundation and roof specifically for the shoot.