Board Thread:Questions and Answers/@comment-8132886-20130707153541/@comment-9839593-20130709081016

dont simply fuse them! say you maxed 2 kotetsu. Then you can fuse one maxed kotetsu into the other kotetsu and the skill level will rise guaranteed. If the fused kotetsu is not maxed then the probability of the skill level to rise is less than 100%.