A lot of people have been asking me this in-game so I decided to make a simple guide on how to make those rare items. I'm only going to use AAs (Angelic Arms, pieces of course) in this guide but it generally applies to all fusible rare items through junior pieces.
What you need: (using AAs for guide but you can use any.)
- 4 Angelic Arm Junior Pieces.
After that, all you have to do is go to the armory and fuse. Amory level does not effect the %.
Fusing 4 Junior pieces gives you 89% chance of getting a Senior piece.
After you get 4 Senior pieces, do the same with the Senior pieces.
The exact % is not listed but it is low. I'm guessing around 1-20~% but it only shows "Lower" as shown below.
My first and only try was a failure.
I really hope this helps answer your questions. If you have anything more to add then simply reply below.
Most of the information I've found out myself, through trail and error. The % is estimated from multiple people including myself.
Cohesion formula no longer needed.