Spirits take a variety of forms and functions. Some spirits can change their physical forms to a greater or lesser extent. Some of them have forms that are sexually compatible with mortal races and this sometimes creates half-spirit children. Half-spirits have most of the same basic physical and mental traits as their mortal parent. There is usually some kind of cosmetic difference such as an unusual hair color, eye color, or skin tone. They might be very beautiful, very ugly or somewhere in between but they are rarely easy to ignore. Depending on the spirit they are descended from, half-spirits may have more radically different traits such as armored skin, natural weaponry, or various supernatural aptitudes. It is common, but far from universal for half-spirits to be favored souls. Half-spirits are not very common but they are common enough that every commoner has at least heard stories about them even if they never met one. Accordingly to folklore, half-spirit are more likely to be conceived the more in sync the mortal and spirit are. Most all stories about mortal-spirit couplings involve a spirit of one of the Nine and a very fervent worshiper of that same deity the spirit is affiliated with. There are exceptions to the rule, but the norm seems to be that the child is raised by their mortal parent and the spirit parent only making occasional appearances in the child's life. Scholars speculate that exemplar spirits are more likely to pursue intimate mortal relations than exogenic spirits though this is hard to prove because exogenic and exemplar spirits are hard to tell apart. Outside of universities and certain erudite temples, most Scarterrans have never heard of the terms "exogenic spirits" and "exemplar spirits. Mera, Nami, and Korus affiliated half-spirits are relatively common. Half-spirits affiliated with Phidas and Khemra are exceedingly rare but not unheard of. Half-spirits affiliated with Hallisan, Greymoria, Zarthus and Maylar fall in between the two extremes.
Second Generation Half-spiritsIf a half-spirit has children, their otherworldly will be diluted. The half-spirit's children might be a little different from their societal norm but not by much. The grandchildren of half-spirit mortals are essentially normal.
RPG Mechanics Use the base traits for the mortal half: human, gnome, elf, whatever else you are playing and apply Merits and Flaws to add a supernatural or exotic touch to the character. Use your imagination, there are no set rules but "Uncanny Appearance" is highly recommended.