Answer: Charles, but with the caveat that you should really wait until their first skills are maxed before upgrading their star level. Focus on Epics (purple backround) instead. First Boudica, then Sun Tzu, then Joan, then Lohar.
Some extra relevant information:
As a new player in Rise of Kingdoms, it’s great that you have unlocked both Minamoto no Yoshitsune and Charles Martel, as they are both powerful commanders in the game. However, when it comes to choosing which one to upgrade to 2 stars first, it ultimately depends on your gameplay style and objectives.
Minamoto no Yoshitsune is a strong cavalry commander known for his high damage output. He is excellent for attacking enemy cities and is often used as a primary commander for rally attacks. If you enjoy an aggressive playstyle and want to focus on conquering enemy territories, upgrading Yoshitsune to 2 stars would be a good choice.
On the other hand, Charles Martel is a versatile infantry commander with strong defensive capabilities. He excels in defending your own cities and provides buffs to infantry troops. If you prioritize building a solid defense and want to protect your own resources and city from enemy attacks, upgrading Charles Martel to 2 stars would be a wise decision.
Ultimately, if you’re unsure about which commander to prioritize, you can consider the type of troops you have trained or plan to train. If you have a larger number of cavalry troops, Minamoto no Yoshitsune would be a better choice as he synergizes well with cavalry. Likewise, if you’ve focused on building infantry troops, Charles Martel would complement your troops more effectively.
Remember, it’s important to research and understand the unique skills and talents of each commander to make an informed decision. Analyze your gameplay objectives and choose the commander that aligns best with your strategy. Happy conquering!