Alternate Tiefling Designs (The Raised Sea)

Designs for a D&D campaign that I run which has non-standard demonic lore, and therefore non-standard tieflings. Brief descriptions of the realms are as follows:
Tarsand: The skeletal demons of this barren, sandy realm are proficient artificers.
Feurefell: A realm of lava, metamorphic and Igneous rock, and crystal.
Xhyktek: A realm of visceral and insect-like demons
Thelast: A realm of ice and snow.
Sworn: A realm of living, sentient, demonic plants
Hehr: A realm of eternal twilight, with demons being made of light and shadow
Foredun: A realm where time is irrelevant and demons are shambling, sentient anachronisms
Loretold: A cerebral realm where demons are more thought than form, with the few structures present being simple white lines against blackness