Saw this book or series on a shelf of a mall store probably in the 80's. Prologue described a war between groups of humans. By exposure or ingestion of some sort of crytal they could control an element like wind or fire. Crystals are sentient. Attempt to control more than one element is fatal because first crystal attacks the second. Main character gets exposed to all crystals at once in a battle to prevent someone else from getting the crystals and successfully gets control of all elements. Crystals had a name...something like sathid. Does anyone recognize the name of the series or book from the plot?