Morale & Fortitude in Wo Long: Fallen Dynasty are dynamic stats used to reach the 'level' of enemies during Missions. Increasing your Morale Rank to the level of an Enemy, will balance the fight, otherwise your enemy would feel overpowered and you would receive great amouint of damage for a simple hit. You can even go past their level, making the fight easier for you and gaining a good advantage against them.
Morale Rank and points will reset everytime you start a new mission. Same applies to Fortitude Rank.
The Morale Rank Stat is found all around, such as the Morale Rank for your Spells or in your HUD during missions, with the following symbol: 
Increase Morale Rank
Whenever you start a mission your Morale Rank will always start at level 1 and you will be able to increase by defeating enemies (Morale Rank can be increased up to 25). Choose your enemies wisely, if an enemy has a higher Morale Rank, you may want to skip them, fight other enemies at your Morale Rank level, increase it and then go back to those Enemies when your Morale Rank is at their level. Defeating Enemies, successfully hitting enemies using Martial Arts or Spells. Landing Fatal Strikes will also increase your Morale.
Losing Morale Rank
Losing Morale Rank is certainly something that you want to avoid. Morale Rank can be decreased by receiving highly damaging blows, like Critical Blows. Being fully defeated by reaching zero health, will lower your Morale Rank.
You can avoid losing all your Morale, by gaining Fortitude. Fortitude can be increased by capturing Flags.
Fortitude & Flags
You can also increase your Morale Rank by interacting with Flags during Missions. Capturing Flags will also increase your Fortitude Rank.
Increasing your Fortitude Rank, will raise your minimum Morale Rank. This means that your Morale Rank will never be lower than your Fortitude Rank, your Morale won't drop lower even if your character dies during a Mission.
Morale Rank in Spells
Spells have a Morale Rank requirements that players must meet to be able to use them, if a Spell has a high Morale Rank requirement, you won't be able to use it until you have defeated a lot of enemies, while low Morale Rank requirement may become available shortly after defeating only a few enemies.
