Definitely would not invest in Nin on him. His Mystery is what I use him for mainly and it's also mainly used for the ignite and poison which to my knowledge is not affected by Tai. Hence, I put Life on him. I ran him with Tai but did not notice a large enough increase due to his mystery not dealing much direct damage.
Hope that helps!
Also keep in mind that growth increases at a steady rate every time your character is Awakened. Awakening = increased growth, which retroactively applies stats to your character. That's why they get stronger when they are Awakened :-) So the current growth rate will change as you Awaken him. Best to look at it as highest growth to lowest growth since that order will never change. This post was last edited by 102***@facebook at 2016-9-21 13:31