I did not suggested that the storyline should be combined , just the reason why other immortals hunt the Dragonborn (my bad, I did not explain clearly my idea) . And NO, I do not think that it needs a custom race .... the immortals came in many shapes , they look like the people who adopted them, from what regions they grow old ... so they can be nords, orcs, highelves etc ... Also they die just by loosing the head ... and doing so a portion of his power (health,magicka,stamina) goes to the other immortal . They should be very VERY strong .... and it's nice to have a storyline with them not just beheadings . I could write the story for some moder who is interested in put it on Skyrim universe .... or the one/ones who want to make this mod(if they will be) can do it them self if they prefer this way .