User blog comment:Kogath/Monster Hunter Stories Discussion/@comment-27116643-20180822043815/@comment-27116643-20180822214224

Oh, the error I'm refering to is in https://monsterhunter.wikia.com/wiki/Kinship_Stone.

Under the Title Emotions it says, "Depending on the rider's and Monstie's emotions, the Kinship Stone can vary in appearance. If they are calm and have a clear mind, the stone is usually a light blue in color. However, if they are filled with hatred and rage, the stone will turn a dark red."

Kinship Stones don't have such a feature where they change color depending on the user's emotions like some mood stone. The closest to how "emotions" have a play in Kinship Stones is their main ability to bond with Monsters and how it's been seen to actually effect them both negatively and positively.

Examples: it saved the Avatar character's main Monster from the Black Blight, but another case a Kinship that was modified and fueld by Cheval's negative emotions infected the Elder Dragon, Versa Pietru, transforming it into Makili Pietru.

The only reason Cheval's Kinship Stone is red is because it was simply designed that way. Most likely to loosely SYMBOLIZE his hatred, rivalry, and intial contrary ideals towards the Avatar character.