Ijsdrakons are found at Shade's poles, in more extreme cold than even Boreans and Nordies can tolerate. They are not normally seen by anyone and generally assumed to be mythical like other dragons.
Ijsdrakons are sapient. They have magic systems completely unlike those used by Shade's bipeds.
The word ijsdrakon is Borean, pronounced ICE-dra-konn. The adjective, also used to refer to their language, is ijsdraken (ice-DRAH-khn).
Ijsdrakons have a system of symbols partway between rune and glyph, but do not tend to engage in physical writing. They have other means of communication too.
In build and shape, something like a cross between an ankylosaurid and a crocodile (see pics linked below for a better idea).
Head large and blunt. Well-defended eyes with good field of vision. The eyes are reflective and opalescent.
They move fluidly - and silently when they want to.
Most do not have visible condensation in their breath.