There is a consistent theme with dragonborn questline here : the quest to become powerful and utilise the force of domination.

main quest paarthurnax telling us that we can feel the desire of domination in our blood

dawnguard is related to molag bal, as a vampire lord it is also asscociated with domination and control, power has rised again.

finally we have dragonborn which again bring us this theme, bend will shout is an excellent example, power become lmmense.


So perhaps at the end our playerborn may become........................molag bal? seems random but it does make some sense, also if this is true it will be a nice suprise (since some dragonborn before become a god, may be last one choose to become a daedra prince)