Just before heading into the Midnight Fane to kick off Chapter 4, play the Crusade mode to get your 4 stats leveled up. Every time you reach a new level you will get a 1-Day Events card talking about reworking that stat. Research it and the next day you visit your Commander's desk in Drezen to go through a scripted sequence and make a choice on how to proceed. Once each stat is at Level 'V' and you complete that scripted sequence you should get the achievement.
From what I can determine, these things increase your score in their respective stats.
Leadership - Researching buffs and recruiting special units
Logistics - Building in your captured forts
Diplomacy - Upgrading Relics
Military - Build units