Tiefling
Basic Information
Anatomy
The most substantial influence on the fiendish features is the fiend that inflicted the taint on the bloodline. Most of the fiends responsible for inflicting the taint are devils because of their tendency to make deals. There are tieflings of other fiends like demons, but they are rarer. Depending on the fiend, the taint can leave the bloodline looking eccentric to appalling.
The ancestry can influence the look in two ways. One way is the type of sin the past few generations veered towards. This can twist the taint ever so slightly to represent that. The other way is the traits non-tiefling ancestors brought to the bloodline. While tieflings always breed true and the magical taint supersedes most other racial traits, dwarven ancestor could make them a bit shorter and bulkier. These changes are slight. Different tiefling bloodlines can mix and express the taint in a newly combined manner. This is the most significant visual change that can happen to a taint.
When a tiefling is growing up, the personal development they go through until they are full-grown can slightly influence the fiendish features. Exaggerating specific features to reflect the personality the tiefling develops in those years.