Offlane Viper build. This is a "2 2 4" build. Single level of poison attack is sufficient for most of the early game. Two levels of Nethertoxin is priority as it scales really well. Depending on how aggressive your lane oponents are prioritise Corrosive Skin.

1 1 4 by lvl 7 - really aggressive lane with a lot of burst.

1 2 3 by lvl 7 - aggressive lane without massive burst.

2 3 1 by lvl 7 - easy peasy lane, dominated by Viper.