The intestinal and gallbladder tissues of the Deep-Sea Hidden Turtle chose a light blue mutation, which is to enhance spell-casting abilities.
Basing on the principles of Biological Alchemy, there is some logic to this action.
It goes without saying what the function of the stomach and intestines is; everyone knows they are related to the digestion of food and the provision of energy to the body.
The bile secreted by the liver, if under intense gastrointestinal activity, will directly participate in the digestion of food, improving the digestive efficiency.
If there isn't much food available for digestion in the stomach, bile will be stored in the gallbladder.
Beyond this, bile also has another function; it can neutralize certain gastric acids, preventing various adverse reactions caused by excessive gastric acid.
The secretion ability of the stomach acid, impacted by mutation, will also be enhanced.