Krubis is the second crime lord boss in High on Life, though High On Life does allow you the flexibility to opt for a showdown with Douglas as your initial choice. To get to Krubis you have to traverse through the vast space terrain of Blim City.
The optimal strategy for dispatching Krubis and depleting his health involves leveraging Kenny's Glob Shot ability to incapacitate him, followed by a swift assault using Knifey while he's vulnerable on the ground. Avoiding his attacks are pretty straightforward—maintain a safe distance, use the rocky pillars for cover, and test out that new ability (dodge) that you gained after the previous boss.
Before you know it you'll be gutting Krubis to collect his bounty and moving on to the next boss!
This achievement is unmissable so no worries there!