Intelligence score measures creatures mental capacity and ability for complex thought. The higher a creature scores, the easier it has for pattern analysis, memory recall and deductive reasoning.
A creature with high Intelligence score can therefore problem-solve complex problems, able to easily speak, read and write languages and can quickly generalize knowledge gained. Low Intelligence however impacts a creature with faulty memory, low pattern recognition and an inability to retain and generalize knowledge.
Spellcasting with Intelligence
Intelligence is the spellcasting ability modifier for Arcane spellcasting. You use your Intelligence whenever a spell refers to your spellcasting ability. You are always proficient with your own spellcasting, where the bonus is level-based, as seen in the Proficiency chapter. {{formula|Spellcasting modifier|your proficiency bonus + your Intelligence modifier
Tiered Proficiency Bonuses
Intelligence allow you to unlock the potential to learn more skills, tools, languages and performances, i.e. Tiered proficiencies.
For each point of Intelligence modifier you have, you may choose two proficiencies of your choice from the tiered proficiencies to gain or lose proficiency in.
When you gain proficiency from Intelligence gain, you may either increase the tier of a proficiency you already know by one, or gain the trained tier in a proficiency of your choice. When you lose proficiency from Intelligence gain, you must decrease the tier of a proficiency you already know by one.
This works retroactively, such that when you permanently increase or decrease your Intelligence modifier, you may either choose one tiered proficiency which gains a tier or one that loses one.