Norns: the opponents?

Grendels and Ettins. Perhaps a harsh thing to name them, but they are the opponents, the enemies, the hurdles in the race for survival for the game's chosen species. They are the most important threat to your Norns. Their natural characteristics have been chosen in order to fulfil that role. Anger and avarice, respectively, and both are contenders in the dubious contest of carrying the most diseases. What if Norns had a simular role? What would their quirk be? 

If our "chosen" species remain the Norns, then the quirk of these opposing Norns would most likely be "lust". These wild norns would be stunted in some simple manner, and these broken genes would quickly pollute the genepool of your own Norns. An inability to use portals would be a suitable taint for example.

In the case a player would not use Norns as their main population and focus, "corruption" of the genepool is no possible threat and another manner of grievance would need to be found. 

Gluttony, like the grendels often posses, could be one option but rather simple and not much of a threat in the food-laden docking station. 

Sloth could be an interesting option, giving these wild Norns a disease that increases sleepiness thoroughly, and a gene counterbalances this. Any creature given this disease that miss the gene would then sleep for most of its time while the vector, the wild Norn, would stay awake to spread it further.

Envy could be another vice, perhaps increasing boredom intensely when among other creatures.

What do you think? What misdeeds would befit the otherwise so cheerful norns? Youre welcome to let me know in the comments!