Star levelling provide the biggest boost to your heroes attack/Intel/politics points. Al though the gem system can be very random. At later levels it can take thousands of gems to level up your pieces. There are cheap methods to upgrade your stars but they still cost a lot. The reward is a very strong hero though which can be far more powerful than your enemies. The maximum points your hero can achieve is a massive 1024. This is a 99 base historic hero wit full lv10 gear, full lv15 stars and Excalibur. Uprise of course can add another 30% to this bringing a massive total of 1356.
|Piece Bonus||Gain from Upgrade||