Arulnithi

Arulnithi was offered the lead role in Pandiraj's Vamsam after his cousin, Udhayanidhi Stalin, had opted out. The film featured him as a young man shying away from the politics of his village, despite claims for him to avenge his father's death. The film, which featured him alongside Sunaina, was heavily promoted in Tamil Nadu, and became a profitable venture at the box-office, garnering positive reviews. His second film was Udhayan in which he played a dual role for the first time. The next film Mouna Guru directed by debutant Santhakumar was critically acclaimed sleeper hit which was also screened at the Hong Kong International Film Festival 2013.

In 2013, he starred in action drama film Thagaraaru was released to average reviews. In 2014, his film Oru Kanniyum Moonu Kalavaanikalum is Chimbu Deven’s trademark style, filled with quirky characters, fantastical elements, and loads of comedy and satire. In 2015, his horror film Demonte Colony, directed by R. Ajay Gnanamuthu, is inspired by real life events centred around a supposedly haunted colony in Chennai called Demonte Colony. The film received mostly positive reviews from critics and became an commercial success at the box office. Thereafter, the comedy Naalu Policeum Nalla Irundha Oorum (2015) which was released to negative reviews. His next film was the crime thriller Aarathu Sinam (2016), which marks the arrival of a remake of yet another brilliant Malayalam film, Jeethu Joseph's Memories that had Prithviraj playing the lead. In Radha Mohan's Brindhavanam (2017), Arulnithi plays a deaf and mute character and his relationship with actor Vivek. Arulnithi's choice of screenplays has always been promising, giving importance to the content, and his next film was Iravukku Aayiram Kangal (2018). Arulnithi fits well into his character and shows maturity with his performance. It was released to positive reviews and performed well at the box office. In 2019, the thriller K-13 is another quality film from Arulnithi who has an eye for good scripts. Arulnithi has once again delivered a subtle performance.

His next movie was the multistarrer drama Kalathil Santhippom (2021) starring with Jiiva. was released to mixed reviews and became an average grosser. In 2022, he starred in thriller films with D Block, Dejavu and Diary. Except for the former film, the latter two films released to positive reviews and was also commercially successful. In 2023, two of his films, Thiruvin Kural and Kazhuvethi Moorkkan. Next, director R. Ajay Gnanamuthu's Demonte Colony 2 (2024) sees the filmmaker reuniting with Arulnithi, along with an intriguing new cast for this horror thriller. Initially met with a decent reception, the film quickly became a box office sensation.