While increased Health is nice, a lot of Prince of Persia: The Lost Crown gets easier when you deal more damage. Upgrading your weapon increases your damage to regular enemies and boss encounters, making it an overall huge upgrade. Here is how to upgrade your weapon in Prince of Persia: The Lost Crown and start dealing more damage.
Where to find the Blacksmith in Prince of Persia: The Lost Crown
If you head to the western side of Haven, you will find a glowing entrance that you can interact with. Interacting with the entrance will take you to Kaheva the Blacksmith. Speaking to Kaheva will give you the option to buy from here. She has some items you can purchase, but more importantly, she can upgrade your weapons, including your melee weapons Qays and Layla.
Your first upgrade increases the melee damage you deal and costs 500 Time Crystals. Purchasing the upgrade will change the Qays and Layla to the +1 variant. As you progress through Prince of Persia: The Lost Crown you can upgrade your weapons further.
Kaheva also has an option called Ancient Power Unearthed. This starts a quest in which Kaheva sends you out to find an item to forge a special item with.
What weapon should you upgrade first in Prince of Persia: The Lost Crown?
I recommend upgrading your melee weapons, Qays & Layla first. Even though upgrading the bow is nice to increase its damage and potential, the bulk of your damage comes from your melee weapons.
Dealing more overall damage from your combos will help with both regular enemies and boss encounters. If you ever find yourself with extra Time Crystals, you can always upgrade your other weapons as well. But upgrading your melee weapons should always be your priority.