Delvians were a species of sentient humanoid plants hailing from the planet Delvia recognizable by their blue skin that was dotted with light green patterns.
In accordance with their plant origins, Delvians rarely exhibited body hair – only a small few were seen to have any body hair at all. Solar radiation, like the light of the sun or a nebulae caused a very pleasurable effect on their bodies known as a photogasm.
While they are a plant-based species Delvians can draw energy from meat in their diet. Under ideal conditions Delvians don't need to ingest meat however if faced with starvation their natural physiology allows them to act in a carnivorous fashion. This transformation only occurs when they have not eaten other foods for too long causing their bodies will eventually switch into a self-defense mode that requires meat to "switch out" again. In this defense mode, the Delvian's body begins to shut down and automatically produces flowering buds that exude a highly toxic pollen. This pollen seriously aggravates allergies in other species, causing bouts of sneezing so severe that any unlucky beings breathing it will be paralyzed by their own sneezes, providing the Delvian with fresh meat ripe for the killing. This pollen has less effect on Peacekeepers than on most races, but even Peacekeepers are incapable of handling it for long. Leviathans seem especially sensitive to this pollen, as it can cause them to go totally blind if they are exposed to it for too long. Starvation also affected a Delvian's mind, causing severe paranoia and even madness. ("Home on the Remains")
Delvians were capable of camouflaging themselves from predators, and despite being evolved flora, Delvians required oxygen to breathe.
Delvians did require planting in soil when ill or drained in order to revitalize themselves and regain energy. Likewise, they were able to make their limbs wither at certain times, turning them quickly into roots, though it took time to heal. ("Out of Their Minds")
The Delvians were a very religious and disciplined species, and many practiced a religion known as the Delvian Seek. The Seek was a search for enlightenment through helping others, renouncing anger, and praying to or worshiping their central deity known simply as the Goddess. A priest of the Delvian Seek was referred to as a Pa'u.
With prayer and deep meditation followers of the Delvian Seek gained a number of psychic abilities which were able to be unlocked by a disciplined mind, aided by the Goddess. One such ability was the sharing of "Unity", the ability for a Delvian to link their mind to that of an other creature allowing for them to communicate on a psychic and spiritual plane. ("Rhapsody in Blue") During "Unity" a Pa'u could impart knowledge or spiritual energy to another using this technique allowing the two Pa'u to share information and powers they have gained as part of the Seek. However "Unity" was only one of the many abilities imparted by the Delvian Seek including creating illusions, block out the senses of another being, causing the lifeforce of another to fade, potentially leading to death, and even the power to shield the minds of others from external influence. All these gifts required both mental fortitude and the Pa'u's own lifeforce, which could leave the participants drained. If the Delvian used up too much of their own energy, they began to weaken, the crown of their head slowly becoming a sticky pulp until eventual death occurred. (Episodes 3.01 - 3.04)
Meditation was used by Delvians to focus themselves on the Seek, but isolation could play havoc with the mind of a Delvian. The Seek could allow the Delvian to control their anger, but could not erase it; Delvians had to be constantly on their guard, lest they succumbed to their darker impulses. The eyes of an angry or murderous Delvian turned a deep blood-red. ("Rhapsody in Blue")
Aside from the Delvian society being religious and disciplined, it was quite open. Delvians frequently meditated in the nude, and spoke freely of all subjects with one another. In the period of time leading up to the Peacekeeper/Scarran War, Delvians were sometimes exiled from their homeworld, simply for following the Delvian Seek. ("Rhapsody in Blue") In any case, Delvians traveled across the universe, setting up other colonies on habitable worlds to which the exiles may go. ("Bone To Be Wild")