The Man Rune is the Form of all mortal sentient beings. The races of the Man Rune include trolls, elves, runners, dwarves, ducks, beastfolk, and triolini, as well as humans. It does not include dragonewts, who enjoy an innate immortality. Nor does it include animals (even if they are capable of sentient thought).
Most stories agree that the world was largely made before mortals ever entered the scene. The gods needed a servant who could communicate with every deity and spirit. Every deity and spirit participated in conjunction to create the Man Rune, called Grandfather Mortal.
Once the Man Rune was created, it too was passed around the Celestial Court. The earliest people were made from mud, they say, or dirt and stone. In those days, people and beasts were not yet differentiated from each other, and thus the Hsunchen, or Beast People, were both people and beasts. As had happened before, the Elemental deities soon experimented with their own people of Darkness, Water, and so forth. Many of the children of these Elemental pairings were shaped by the Man form and were the founders of the many tribes of humankind.
Grandfather Mortal is the exemplary model of behavior and decision making for all mortals. He (or often she) was the first entity to experience Death, when Humakt was testing the New Power during a critical turning point in the Gods War.
Do Elves have the Man Rune rather than the Plant Rune? Elves are Man and Plant, all Aldryami have the Plant Rune. Not all have the Man Rune.
What would an elf with a high Man Rune affinity be like? More human looking and behaving.
The essential Mortal-ness of all those who share the Man Rune is what unites humans, elves, trolls, dwarves, triolini, etc. Sure the trolls are Dark People and the elves are Plant People, the triolini are Water People and the humans are Everything People, but they are all People.
The dragonewts are something else though. They are not mortal – they die and are reborn with their memories and consciousness intact. They see Death as a mirage, a mere transitory change, and even embrace it to transform themselves.