659. An ultimate secret weapon must be single-user only. If the weapon falls into the wrong hands, roll one d4 to see if it breaks.
660. Volcanos are always active. Just the smallest misstep could kill you, because dormant volcanos are lame.
661. One shall not mention the periodic table of the elements, because everyone knows the real elements are fire, air, water, and earth (substitute with light, shadow, or ice as needed).
662. The person who brings a sword into the gunfight normally wins, due to chopping 600+km/h speed bullets by reflex
663. Balance must be kept between everything, until a plot-convenient point of the story.
664. Sailing too far west is a very, very, bad idea, as all maps show that there is the edge of the world there, and that'd be bad to fall off.
665. Summoning rituals must take more than 2 minutes, otherwise it wouldn't be cool enough.
666. Defeated does not always mean dead, and vice versa.