Anbe Sivam

Two men waiting for a flight to Chennai at the Biju Patnaik International Airport in Bhubaneswar engage in conversation. One is an advertisement filmmaker, Anbarasu (R. Madhavan), who prefers the abbreviated name "A.Â Aras", and the other is a scarred, deformed but witty socialist, Nallasivam, alias "Nalla" (Kamal Haasan). When the flight is cancelled due to heavy rain, Aras suspects Nalla is a terrorist and informs the authorities, only to discover that he was mistaken. When the entire city becomes flooded, the two men find themselves forced to share a room for the night. Both need to return to Chennai: Aras to be present at his wedding, and Nalla so he can deliver a â¹3,200,000[a] cheque, recently awarded to him after he won a court case, to a group of union workers. After a traumatic night, and no hope for a flight, the two men take a bus to board the Coromandel Express train. Aras' bag gets stolen on the way leaving him with only his credit card, which no-one accepts. Using his presence of mind, Nalla repeatedly bails Aras out of trouble while Aras tries escaping from him at every juncture, only to end up with him again. While waiting for the train at the Ichchapuram railway station, Nalla begins to tell Aras his story.
A few years earlier, a healthy Nalla took part in various street theatre performances protesting against multinational corporation-driven industrialisation, that resulted in the marginalisation of the labour force. He was at odds with Kandasamy Padayatchi (Nassar), a manipulative factory owner who refused to give his workers a raise. Nalla satirically imitated Padayatchi in many of his shows. However, in an unexpected turn of events, Nalla and Padayatchi's daughter Balasaraswathi, called Bala (Kiran Rathod), fell in love with each other. Realising their chances of getting together would be slim if Padayatchi knew about their relationship, Nalla and Bala decided to elope to Kerala. Nalla boarded a bus bound for Kerala, and on his way to meet Bala, the bus crashed on a hillside leaving him scarred, disfigured, and partially paralysed for life. After recovering from his wounds, he visited Bala only to be informed by Padayatchi that his daughter was already married and has settled abroad. Padayatchi had earlier lied to Bala that Nalla died in the accident. It was also at this time that Nalla became a firm believer in kindness and love. Despite suffering from an inferiority complex due to his scarred and deformed body, Nalla performs community service and social work with renewed fervour while continuing to fight for union causes.
Upon their arrival at Chennai, Aras delivers Nalla's cheque to the union workers. He invites Nalla to his wedding, where, to his utter astonishment, Nalla sees that Aras's bride is Bala. Padayatchi spots Nalla and asks him what he is doing there, to which Nalla replies that he was invited by Aras to the wedding. Nalla then persuades Padayatchi to sign the papers which will help the workers obtain a raise. To prevent disruption at the wedding and avoid damaging his reputation, Padayatchi yields to Nalla's demands. After signing the papers, Padayatchi instructs his assistant (Santhana Bharathi) to eliminate Nalla. Padayatchi's assistant, however, has a change of heart as he is about to kill Nalla. Padayatchi's assistant believes that the wrongful deeds he committed for Padayatchi resulted in the death of the assistant's daughter. Padayatchi's assistant requests Nalla to leave the city and stay as far away from Padayatchi as possible; Nalla assents and walks away.

Question: Which two characters decide to elope?
Answer: Nalla and Bala