Micelus' humans are getting the most attention because they have an actual description. A vague one-liner, unless extremely clever, is not enough to make a race interesting and unique.
Basically this.
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Dragonfalls: A hundred kilometre tall obsidian-tower with a smooth, frictionless surface. At the top of the tower if the dragonfount, which spouts out an endless geyser of hot as dragonfire liquid water, cascading down the sides in a circular waterfall. As it fall the water slowly cools, being merely boiling at the bottom. If a fish, reptile or lesser dragon manages to swim up the waterfall and reach the top, they are rewarded with a transformation into a true dragon. If they fly, teleport or otherwise cheat somehow, they fail to get any reward. Gaining immunity to heat doesn't count as cheating. The top of the of the tower is permanently shrouded in a titanic aurora.
Art of Breath: Magic focused on the act of breathing. It's main use is turning expelled breath into strong gales, breathing inward gaining great sucking force, or enhancing breath weapons. Powered by fat reserves.
Art of Sky: Practitioners gain control over the weather, with the magic powered by altitude (as measured from the molten planet core of the world). As such it is weaker/more dangerous on the hollow inside surface of the planet than the outside. Particularly ambitious magic can suck you straight to a fiery death in the molten core/cause a lethal crash into the ground if you're not careful. Users often fly up as high as they can before beginning any spells of this magic.
Art of Scales: A purely defensive magic, that can enhance the defensive powers of the practitioner, hardening their scales, giving them immunity to certain type of damage like acid or reflecting arrows back at the caster for example. Personal magic that works on the caster only, and only works on creatures with scales. Powered by thaums.
Art of Fire: Magic that creates and controls fire. Fireballs, firestorms etc. Can be used to enhance firebreath, and synergises with Art of Breath if both are used to do this. Powered by sight, the user giving up seconds/minutes/hours/days of sight depending upon the power his spells. If already
permanently blind (whether from using Art of Fire or something else, non-permanent blindness just means the duration of the blindness increases. Duration longer than century functions as permanent for the purposes of Art of Fire) he must choose an additional sense to lose access to. If completely senseless, the caster cannot use Art of Fire.
Cursing Lightning Pterodactyls with a Major Phobia of Dragons
Cursing Kappa with BlindnessWould dragon sphere discounts apply to any of these? If it doesn't already apply to the arts, would it apply to them if I made them dragon only?
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Boring a large hole through the crust between the inner hollow world and the outer surface world.
Planning to pierce the heavens?
Making a gateway city between the two worlds actually. It'd be a trading superpower hopefully.