As Liang Shu moves from being a man dealing merely with minor local issues, to someone whose deeds cause ramifications throughout the land, he can begin to earn Renown. Renown, much like Wealth and Guanxi, is a currency that can be earned and spent. It is more difficult to gain than other forms of currency, however, with only a few Actions providing means to increase it. The main way to gain Renown is through the deeds of Liang Shu and his faction. Winning battles, defeating famed foes, taking part in great military campaigns, providing good service for the Han, befriending very high ranked officials and marrying into prestigious families are all ways to earn Renown, although there are many others. Renown can also be earned by being promoted to military, civil, government or noble ranks. As a currency, Renown can be spent in a few ways. You may be able to use your Renown to sway famous officers to pledge themselves to your banner, and you can also use it to help negotiate diplomatic deals with other factions, or earn favours from powerful patrons.
The primary use for Renown, however, is the purchasing of Reforms. Reforms are powerful buffs that effect your entire faction, and persist even after Liang Shu has died. Reforms can be purchased at any time, and more will unlock for availability, much like Improvements. Unlike Improvements, which only matter for your Estate, Reforms "follow" you no matter where you go or what position you have, and cannot be removed. Early Reforms only cost Renown, but more powerful Reforms will require Wealth or Guanxi as well. Scientific research, encountering mystics and sages, possessing particular items and recruiting certain Legendary officers can also unlock new Reforms.
To begin with, as a man who only possesses what is functionally a private army and de facto ownership of a burgeoning town, Liang SHu only has accesses to a small number of Reforms, primarily military. Social, civil, technological and commercial Reforms will become available only as he becomes a true warlord and faction leader in his own right. It is up to you how you spend your Renown. Early on, do you use it to bolster the Azure Lances, or do you save it for when Liang Shu is able to claim ownership over large swathes of land? Or, do you perhaps use your Renown to "trade" with influential persons, to perhaps speed up Liang Shu's career?