Shadowrun: Hong Kong - Extended Edition

During the Outsider mission, after getting into Magpie’s storeroom and searching the memento each time, you’ll meet Gaichu. Make a save here if you want to get the other achievement for Gaichu joining your team.

Choose to attack him then return to the Whampoan Elders after to report. The achievement popped for me about a minute later after I left their area and started walking back to the subway.