What's the fastest and laziest class to level, like naked, without help.

[Haghar]

You shouldn't be hunting even cons most of the time. Unless you have something like Tash/Malo you can expect an inordinate amount of resists - this has nothing to do with your skill level as a Necro, only your level.

In general, your goal should be to hunt the lowest dark blues you can find as they have the maximum experience per effort, and lowest risk of death.