Promotion Cabochon
Idea for a new inventory item:
Many times it seems a pity to invest so much time and resources into a champion in the game only to some day be forced to stop using that champion because it reaches that cap of its power and you've moved on to higher-star champions. It happens early in the game when you get your first few 2* champions and stop using the 1*s you begin with, and then again when you move on from 2*s to 3*s and 3*s to 4*s and 4*s to 5*s. It would be great if there were some rare items that made it possible to promote these champions you may have grown attached to, rather than leave them behind.
So...
Promotion Cabochons
These items can be used to promote any champion in your inventory one star level. They should be limited to a specific star level, and perhaps a specific class, and should promote them one star level while reducing their rank by one.
So for example a 1-star Cabochon can be used to transform a fully leveled up Rank 2 1-star champion into a Rank 1 Level 10 2-star champion.
A 2-star Cabochon could turn a 2/20 2-star into a 1/10 3-star; or a 3/30 2-star into a 2/20 3-star.
A 3-star Cabochon could turn a 4/40 3-star champion into a 3/30 4* champion, etc.
A 5-star Cabochon could turn a 5/50 4-star champion into a 4/55 5-star, etc.
Signature levels should stay the same, with the downside being if you upgrade a max sig level 4-star to a 5-star you only would have half max level since 5-star have a higher number of sig levels.
Would be a cool addition to the game.