If Helios, the sun god is a myth, who drives the chariot from east to west everyday to make the sunrise and sunset? If Zeus the thunder god is a myth, who creates the thunder when it rains? If the tooth fairy is a myth, who gives new teeth to kids once they fall? These questions are as invalid as asking "if the Khandas are anatta, who realizes the Dhamma". Because they all assume that for an event to take place, there should be a doer.
Realization is a momentary mental event that is caused. Realization does not require a self. Just like any other caused event in nature, it only requires causes to arise. In this case, right concentration is the proximate cause of wisdom(Panna).