WHAT PLANES CAN I "SEE"?
Magical Conductivity score (see1 - 3: None whatsoever. May not use spells in any form. No witchsight. However, +5% resistance to a Battle of Wills from an enemy spell caster. May not be a Mage.
4 - 7: Very little. No witchsight. May not use spells in any form. May not be a Mage.
8 - 12: Average. No witchsight. May become a Mage. May not learn spells unless a Mage, but may cast spells from scrolls, books, magic items with embedded matrices, etc.
13 - 15: Good. Witchsight onto Second Plane. May become a Mage. If not a Mage, can learn up to 1 spell, and has 25% chance of knowing one spell already that does not count towards total (flip a coin - heads, the player may choose, tails select the spell randomly). May cast spells from items.
16 - 17: Superb. Witchsight onto Third Plane. If not a spellcaster, can learn up to 2 spells. 50% chance of already knowing one spell that does not count towards total, and 25% chance of knowing two (flip a coin for each - heads, the player may choose, tails select the spell randomly).
18 - 20: Overwhelming. Witchsight onto Fourth Plane, plus 1d3-1 more. If not a spellcaster, knows 2 random spells, and 1d2 more of the player’s choice.
FIRST PLANE SIGHT
Anybody (mortal) can see (and feel) the First Plane. It is the Plane of the Material and of Sensations. It’s the normal plane that we mostly interact with. Things appear as they are according to physical laws, and sensations are experienced by living things through processes such as light diffusion interacting with retinas and being transmitted to the brain via electrical signals. These physical phenomena are easily influenced by magic. Glamours are easy to produce, and many creatures are not detectable at all on the First Plane because they do not have corporeal bodies capable of effecting physical phenomena.
SECOND PLANE SIGHT
"Witch Sight" displays things closer to their True nature. The more common varieties of spirits will be visible, floating in incandescent masses around certain locus points. Beings may glow with auras that correspond to their emotions or desires. Most magical items will be noticeable. You will be able to see many invisible things. It requires more effort to create glamours that extend to each subsequent Plane. Note that cats can see onto the Second Plane, and many dogs can smell onto it.
THIRD PLANE SIGHT
More powerful spirits are visible only on the Third Plane. Normally only powerful or paranoid humans will extend glamours past the Third Plane. You will be able to see most invisible things, including some truly bizarre images that do not match the physical world in any way. This character can also sense other magicians or people with great Power or a great capacity for magic. They will somehow signify their ability - perhaps they glow brightly, have a third eye on their forehead, perhaps they look exactly the same on all planes, etc - it may or may not differ from person to person.
FOURTH PLANE SIGHT
The Fourth Plane is where the most powerful spirits reside. Here, shapes are bizarre and mirror the true forms of the things within. Those with sight onto the Fourth Plane can begin to see sapient beings as they truly are, usually through obtuse symbolism. You will be able to see almost all invisible things and note almost all magic items. You will also be able to quickly identify other mages or great beings by their Power or Magical Aptitude. You will also be able to gauge their power relative to your own. People with great Power will be like beacons in the night, visible from far away.
FIFTH & SIXTH PLANE SIGHT
The Fifth and Sixth Planes bear very little resemblance to the 1st, such that it can be difficult even to relate them to normal experience. The air, sky, ground and other creatures are all perceived differently in a way that is so alien to normal human thought as to defy imagination. The air will be thick with near-True “shapes” of all the myriad spirits of every dimension - both those of the underworld and elsewhere.
Beyond this exists the God-Realm and the Hero-Realm, which are not so much simultaneous overlapping dimensions but separate realms of the unconscious mind.