The Helvan are a xenophobic humanoid species. Physiologically, Helvan are humanoid with their only known external difference from Humans being a series of horizontal ridges down the back of their neck and along their spine. Helvan traditionally mate for life. When two Helvan have intimate relations, they experience olan'vora - "the shared heart". This makes their body chemistry interdependent, causing withdrawal symptoms if the two people separate. The effect gets stronger with each mating and separation can be fatal. An Earth ship encountered a Helvan Generational Ship under attack by Fen Domar soldiers. The humans managed to get 7 Billion Helvan. Those Helvan were transported to Earth and colonies.