Complex sentence: Getafix, who identifies the malady as attempted murder by poison, agrees to brew an antidote for Sinusitus, however requires an essential ingredient... a flower called the silver star (edelweiss), which only grows on the highest mountains of Helvetia.
Split into simpler sentences: Getafix, who identifies the malady as attempted murder by poison, agrees to brew an antidote for Sinusitus. However he requires an essential ingredient, a flower called the silver star (edelweiss), which only grows on the highest mountains of Helvetia.