The pure doppelganger will show up when you have high corruption. (enough to get kicked out of the bastion)I also have removed the corruption from those achievements for 0.7.3
Oh I see, I assumed that:Low/No Corruption - PureHigh Corruption - CorruptedThank you for the clarification.
The doppelganger is your opposite so :
High corruption - pure doppelganger
Low corruption - corrupted doppelganger
How high is high? And can I meet it again after defeating it?
It didn't trigger till I got overwhelming corruption (500 corruption I think?) and yes you can meet it again in the same run.
Thanks for the information.