Life gained - increases the overall life point of your team

Similar to strengthening your equipment, the first five skills refer to your basic attributes that you can see on your main character interface. Pretty self explanatory, leveling up attack gains will increase your attack etc.

The last five you can see in the additional attributes section of the details. *ion is to increase the chance of causing higher damage to your opponent in the range of damage that you can make. Damage reduction is the counter of this, which reduces the damage caused by your opponent. Life recovery is just the amount of life point restored to your team after each round.

I would suggest leveling up the first five first, as they have a greater effect on your power. It has been experimentally tested by people from the Chinese version that the two *ions make very little difference in your battle, so unless your have maxed all the other ones and still got a lot of contributions left, they are not recommended.