A simple marking that covers the belly of your dragon in a solid patch of color that is roughly symmetrical. At least 1/3rd of the mark will appear in the dark red area. The light red area shows the approximate maximum.
Shape Rules
It can cover the entirety of your dragon’s limbs, excluding the upper side of wings. It should not extend all the way to the spine of your dragon, the crest of your dragon, or the top of your dragon’s snout. Reference the underbelly of dogs and orcas if you are having difficulty with it! Here are some examples of shaping.
Minimum Underbelly 
Alternate Shaping & Soft Edges 
More Fluid Shaping 
Minimum area in alternate location.
Texture Rules
The dark red area shows the minimum size, although it may be in slightly different locations.
Color Rules
Underbelly may be any color in the elemental color palette as well as black or white.
Layering Rules
This marking can go above or beneath other markings. It will not cover top layer markings.
Effect on Modifiers & Physical Traits
It may affect modifiers, skin, nails, ears, and similar things where it touches.
Charged Underbelly
Charged Underbelly may display a gradient between two colors. These colors must still follow regular marking rules.