I plan to end fantasy stories line with destroying magic - and let that world to be without magic - to it would be converted into SF/utopistic (or so) world.
Currently I have following idea: Convert magic to else (classic) materials (and also natural rules, as described below).
This way has been already started - when conversion of magic into classic materials was discovered and industrial way of this conversion was prepared for usage. However, this process is not perfect and small amount of magic stays.
Conversion of magic into classic materials would be ended in great battle, when rest of magic would be definitely converted into various classic materials (rather: elements, like iron, copper, carbon and so on, including heavy ones like uranium or so) and natural rules (gravity or so).
Also, this change would bring new type of magic: magic that is (due to knowledge) not distinguishable from technology. This type of magic was first described by Icefingers and Warmsteel, but this work had to be held because most people did not accept it (and they did not believed in this work at first, too).
But of course, this change would, due to speed of final step, cause terrible chaos leading to very increased mortality and rise of religiosity and belief (and also wrath of gods on people).
But what else way to use to destroy magic - without destroying whole world (if it is magic world)?