Merging

In the Spirits menu, the left-most tab is Merge. Here, you can strengthen a spirit by merging other spirits into it.

The base cost to merge is 100 spirit points per enhancer spirit plus an additional 10 spirit points for each level of the base spirit minus 1. So, if your base spirit is level 15, it will cost an additional 140 spirit points per enhancer spirit to merge spirits into this base spirit.

Experience gained from merging is imprecisely represented by a percentage bar.

Merging spirits of the same element results in 150% the normal experience gain. Furthermore, merging the same spirits into each other can result in bonus stats. Last, if a spirit has reach maximum level, you can merge the same spirit into it to increase its maximum level.

There are a number of spirits created specifically for merging purposes. These are the Jack, Queen, King, and Joker of each element. These spirits are always at max level. The Jack, Queen, and King provide a large experience boost, and the Joker can be used to increase a spirit's maximum level as though it were the exact same spirit.