TERRIANS

Terrians are the most important people on G-889. They live undreground into caves. They've got a special link with the planet, they dominate it, and obviously (in spite of all the others G-889 creatures) without their existence the planet will die.
The hypothesis stated by Julia's scientific researches concerning the terrians evolution says that long ago they were maybe like humans being with emotions, qualities and faults and that it could be possible that living on G-889 the humans evolution will be the same.
Indeed, in "After the thaw" it is stated that terrians millions years ago decided to abandon their emotions in order to live in rightousness (without happiness, without sadness, without forgiveness...).
In that way, Terrians are very peacefull and righteous.And they really seem to be able to accept the cohabitation with humans (they did ti with the penal colonists and they do it now with the Eden group), even if sometimes there are some misunderstandings with the crew ( when they are trying to protect their dominion).
Apparently, Terrians found a special link with Ulysses that they have choosen to be a bridge  between humans and terrians, in order to build a world together.
They've found also a special link with Alonzo who permit them to communicate with the crew by dream.
Dream seems to be the only way of communication for Terrians.