Use a dictionary. Usages differ widely, and games like WoW may have their own definitions. Other communities impose other definitions. Readers of Haryy Potter, for example, will have very precise definitions that are at odds with those of WoW. Phrases such as 'the power of light and fire' sound to me as though they come from something like WoW (which, for the many who won't know, is an online role-playing game called World of Warcraft).
Generally, a 'magician' is the same as a conjuror: that is a word that has a real-world use - there are people who earn their living as magicians: the word is on their passports; they are entertainers of a particular kind. The other words all mean whatever they mean to whoever uses them, in the contexts where they are used: for example, a Druid - Wikipedia, the free encyclopedia may have particular meanings for some of these other terms that are meaningful only to other druids.