After reviewing a bit of Highlander (specifically the first one) some things clicked in my head.
There is this whole thing in Highlander about the Prize (essentially, a version of ascension with the option of mortality), and with it direct the course of humanity.
Highlander immortals are not truly immortal but can die from beheading. Should they kill another immortal, they gain something called the Quickening - which also occurs when they connect to the world around them. Basically, it's tapping into energy. When they have killed another immortal, they seem to get that immortals energy and power. In the later movies I think it can even turn them good or evil, depending on what the immortal they killed was like. Finally, though it isn't the case in the first film in the later films the "gathering" (an event where all the immortals are drawn to America (of all places) to kill each other and gain the "Prize" turns out to be a cycle.
All of this is important to know considering some of the latest reveals.
I am wondering if the starborn are similar beings. Perhaps they are immortals, or immortals in the making - scions of a sort. They have the option to choose. I say this because of Mab's comment to Dresden about how whilst immortality offers significant advantage, it is no substitute for intelligence. When Eb looks upset that she says this to Dresden, she smoothly cuts him off before he can interject and says "should that ever become necessary, for some bizarre reason" - a not at all important hint.
Drakul, Listen and Dresden are all the known starborn. Two mortals and a possible immortal.
The possible (still mortal) starborn still roaming around are: Elaine, Marcone, Nicodemus, Rashid, Riley (there's a theory floating around), Kumori (if she isn't Elaine), Cowl (possibly).
The possible (immortal) starborn still roaming around are: Mab, Vadderung, Titania (given that she might be Mab's actual twin).
The possible (mortal) starborn but are deceased (probably): The OG Merlin Emrys, Kemmler (almost certainly).
Thoughts?