Question: what is the difference between mythic and mythic keystone?
Answer: The main differences between Mythic+ and Mythic dungeons are that in Mythic+ you have time limit (about 30-40 minutes), bosses and mobs are stronger and you get loot only after completing full dungeon. You need a key. What is the key? From last boss in Mythic Dungeon you will loot Mythic Keystone in specific dungeon.