When Siva said to Ganesha and Murugan, “Whoever goes around the universe first will get this mango,” Murugan immediately took off on his peacock to go around the universe, while Ganesha was thinking how to do that (He has got only a slow moving mouse). When Murugan was going around, He met Rishi Ahasthir. Murugan created Tamil language and taught Tamil to Ahasthir (so, Ahasthir was the first Tamil student). This delayed Murugan and in the mean time Ganesha circumambulated (pradakshina) Siva and Parvathi and received the Mango, and Murugan arrived just in time (teaching us that parents are the universe). The Tamil word “Murugan” means “Beautiful.” No wonder Murugan created that word to describe Him.
In our teachings we're both monistic and theistic. In the beliefs of Saivism the idea of the three worlds is the basis and key to understanding temple worship, theism. The inner worlds are there to help you. The essence of the soul is already the same as the essence of God Siva, monism. You just have to find it.