[@Kazemitsu]You're limited to what has been shown in the show. The relatively closest thing you can get to that is the demi human lizardmen.

http://overlordmaruyama.wikia.com/wiki/Lizardman

If I'm over looking some sort of dragon-kin species that has been in the show than you can correct me on that matter. If you want poison you can specialize in rogues with daggers, and such, or a black mage type job class that uses poison debuffs and the like. I know things like what you describe are present in DnD but I have not been into the series long enough to know if they are in Yggdrasil.