In the play Night of Kings, a group sets a trap to make a fool of Malvolio, a character who can not have fun let alone accept the fun of others. A second character who is not imbued with the spirit of fun on that Kings Day is Olivia, who mourns the loss of her brother - until it loses its importance when she meets Cesario and falls in love with him. Here comes Shakespearean genius, masterfully dealing with issues of unrequited love, impossible affections, false identities, and leading the comic to a happy ending of love affairs. In this concept, it is correct to say that the theme that is central to the Night of Kings is love.
Love is the answer you are looking for. Orsino is in love with Olivia. Olivia is in love with Cesario. Viola is in love with Orsino. Therefore your answer is Love.
