Cognition affects how well you use your Intellect. It affects things such as how well you pay attention to the world around you, how easily you apply knowledge, and how quickly you regenerate your magic.
You regenerate 5 magic per rotation at the beginning of your turn. For each point of Cognition you have you regenerate an additional point of magic each rotation.
Outside of combat you regenerate magic every minute, not every rotation.
Each time you gain a rank in a class with the Magic Focused trait you gain a boost to your magic regeneration equal to the rank (Rank 0 = +0, Rank 1 = +1 (total +1), Rank 5 = +5 (+15 total))
Cognition based Skills:
Mugen guns
This dictates your ability to use Mugen guns.
These are magic based weapons that require a power source (Usually a specific spell) in order to be fired. They vary greatly in their damage, fire rate, and magic cost making them a versatile but rare weapon.
Traps
Your ability to use and disarm traps. A must for any aspiring rogue.
Lockpick
Your ability to unlock locked things. A thief's best friend.
Awareness
This is your situational awareness and ability to notice and spot things, such as traps, sneaking enemies, items, hidden things, see from a distance, etc.
This is a very versatile ability that is recommended for most characters.
Survival
Your ability to survive in the wilderness.
Better survivalists can easily make camp, find food, find water, and avoid roaming wildlife.
Collecting meat and skinning animals, making a fire, and gathering materials from the surrounding area all use this skill.
Tracking
Your ability to read a trail and follow it. This helps when a target has escaped, when hunting for game, and when looking to see if anyone is nearby.