Boundless AbilityG 5

This can be found in The Maze Engine Campaign, Act 3, Mission 6: Strange Concoctions, which becomes available from Bruenor Battlehammer in Mantol-Derith about 15 days into the Campaign.

Bruenor will send you to see Lucas Shaneway III who will challenge you to a drinking contest. You will be asked to choose which attribute you want to use to try and beat Lucas with, with the exception of Strength.

Your success at each drink is based on classic D&D dice rolls, so there's no guaranteed way to win it. If you succeed at all three drinking challenges, you will unlock the achievement.