Although immortal, this only refers to natural death. A Timenoid can still be killed, although not quite as easily as a human due to them being able to regenerate themselves to an extent.
Timenoids are rumoured to have blue or black blood, which would explain the pale, sometimes pearl blue tint to their skin.
Timenoids are unable to have children, and so if they desire one, they tend to adopt human babies and convert them into Timenoids. The process of turning a human into a Timenoid is unknown, but rumoured to be a painful and terrifying experience. Due to this, humans who have requested this process have often been declined by Timenoids. Humans tend to hunger for immortality, and have often attacked Timenoids for not sharing their "gift".
Timenoids are able to levitate, using a hum of energy to keep them afloat.
Timenoids were once humans, and therefore look human despite their pale white/pearl blue tinted skin tone.
Jake: You don't wanna go exploring that place, homie. I heard the place is haunted by Timenoids.