“ Dust Elemental
https://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=1594
At the corner of air and earth elemental planes resides the dust Elemental, a growing threat to Parisia. With it's powerful choking attack, this creature is a threat to the city. More and more of them are appearing in town, spawned from the many dust devils, a frequent foe of the party, they come in size from 3 HD to 20 HD. Why are there so many? Why in the city?”
“ The members of the party has unknowingly been infected by a mysterious plague and have been spreading the virus for quite some time now while adventuring. They start to hear rumors of all the cities in quarantine after they travelled trough. Will they discover the source of this? Will people start to avoid them, try to kill them?”
“ A demon in human shape that murders travellers, however, he can only travel a certain distance from his home.One the adventures have passed that point, he is no threat to them.”