Eka is Bangun's second-in-command in Bangun's Gang. He is actually a former undercover police officer infiltrating Bangun's Gang before Eka swore loyalty to Bangun after he was abandoned by his superiors.
The Raid: Berandal
Eka was first appeared when he, alongside Bangun and Uco accepting Rama into their gang.
Trivia
Eka and Ryuuichi's actors (Oka Antara and Kazuki Kitamura respectively) are previously appeared on Killers, an Indonesian-Japanese psychological thriller film directed by Indonesian director duo The Mo Brothers.