Plagues and other great diseases are important parts of history and some settings. They defy man and may even defy God in their swift and terrible punishment upon the body of society.
My issue with modifying/removing dwarves and elves is that the PC’s may want to play them.
One of the most powerful tools found in the World Building 102b article is the Worksheet. Here is a place to put the settings you might make with them.
Meta energy...lent by lunos of the seven skys, father of the dragongods, has the power to alter events, rippling through time and space, no other form of energy is stronger, with the ability to even destory planets.It rips apart sheilds by going back in time before they were brought up. No weapon can withstand the force of such It is a power usable only by families bloodline, and those we have chosen to gift with miniscule amounts of its power. It not being of this plane, isn't even subjective to the so called "gods" here. Different worlds, different levels of power.
It is a power of change and manipulation, essentially leaving us to create with it what we will, if our mind is strong enough to do so.
Large amounts of this inserted into any one being/energy will cause them to implode, ripping themselves apart and sucked into another dimension entirely.
The limitations of meta are only set by ones mind, an open mind has no limits to the powers of meta.