Gives a chance of significantly increasing the damage from the impale skill.

The in game help reads:

Skill duration: random.
Type of skill : neutral skill.
Affecting stats: Str/Dex.
It uses no endurance points.
While impaling an opponent is a difficult task, those
who can execute this maneuver with ease can sometimes
having once impaled their foe, twist their weapon so
it rips and tears the victim, until the weapon is pulled
completely out of their victim. Once this is done, another
impaling maneuver can be done, before the victim has time
to react.

This skill should act as a mastery for the spells regenerate rift entity and dimensional leech, allowing more effect per spell point spent.

The in game help reads:

Skill duration: random.
Type of skill : automatic skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
The flow of energy from the rift worlds is difficult to manipulate and direct.
This skill not only increases the amount of energy available to the
riftwalker, it also allows the energy to be more accurately focused.

This skill helps various rift spells in various ways. Probably.

It’s suspected one shouldn’t go crazy cranking this skill to super high levels.

If you want more detailed information, use the command “tell moss I have some bribe money for you.” and follow the instructions you’re given.

The in game help reads:

Skill duration: random.
Type of skill : automatic skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
Knowing entity life forms is an integral part of the guild of riftwalkers.
This skill, although difficult to learn, will have very beneficial effects on
a number of guild spells.

This skill can let you know how badly your offensive spells are harming a monster. When you blast a monster, you may get a line informing you of how much of the damage the monster managed to resist, if any.

This skill is very useful to help you avoid wasting time and energy, either by telling you when to try a different form of damage or to skip a monster entirely. It works on more than 99% of the monsters in the game. It is known to be unreliable when paired with weak spells like ‘magic missile’.

This skill can produce the following messages indicating resistance levels:

Monstername screams in pain. –> About 0% resistant.
Monstername writhes in agony. –> About 20% resistant.
Monstername shudders from the force of the attack. –> About 40% resistant.
Monstername grunts from the pain. –> About 60% resistant.
Monstername winces a little from the pain. –> About 80% resistant.
Monstername shrugs off the attack –> About 100% resistant.

The in game help reads:

Skill duration: random.
Type of skill : neutral skill (arcane skill).
Affecting stats: Wi.
It uses no endurance points.
As powerful as magic is, it does have drawbacks.
The most common way magic is used is to be wielded as
a weapon. Due to the nature of magic, the effects of
magical spells may not be apparent. Some creatures 
themselves are born of magic, with powers
to ward off magical attacks. Others have other ways
to defeat offensive magic cast upon them. In order to
efficiently use magic to defeat a foe, means being able
to tell if your attacks are having any affect. By 
carefully studying the effects of magic one can
deduce his effectiveness against his enemy. Of course
there is said to be magic which can hide the true
effects of magic from even those most proficient at
this skill. It is said that wisdom may help discern
the effects of spells using this power.

Quick chant is an essential skill anyone who regularly casts spells that take a long time to use. Quick chant essentially lets you get two or even three rounds worth of spellcasting done in one round. This skill by itself can’t let you complete spells in less than one round however.

Quick chant’s chance of working is heavily influenced by your knowledge of the spell being cast. 100% quick chant is much less useful if you’re trying to cast a spell you only have at 10%.

You can toggle quick chant on or off with ‘use quick chant’.

The in game help reads:

Skill duration: random.
Type of skill : spell casting skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
Anyone who employs magic of one sort or another, will
testify that casting spells takes time. The mysterious
power, which mortals call magic, does not jump ready for ones
use at a single thought. It takes time and concentration for one
who wishes to employ magic, mainly in the form of spells.
Of course, there are times when that amount of time needed for
one to cast a spell is not available. Fortunately many years ago,
a scholar in the ways of magic discovered that by using carefully
crafted abbreviations, one could speak the words needed to harness
the power of magic more quickly, just as we use contractions and 
slang to ease our verbal form of communication. Of course, this is   
a much more refined art than simple speech. But given the proper
training and instruction, one can use these techniques to shorten
the time they require to wield their magical powers.

This skill will increase the chance of your rift entity informing you when a spell effect or stun drops from it. It may also help retain control for longer periods of time. Train this skill, but not at the expense of your other abilities.

The in game help reads:

Skill duration: random.
Type of skill : automatic skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
A skilled riftwalker must know how to control his entity, and this skill will
assist him/her in a variety of spells. Amongst other things, this skill will
help a riftwalker to sense if a spell effect drops from his entity.

Riftwalkers must periodically wander the rift world to ensnare entities, either because they want a new entity type, or because they need to feed an existing entity. This skill reduces the spellpoint loss of being in the rift world, enabling longer visits. If you are spending large periods of time using the ‘seek’ command in the rifts, this skill may prove valuable.

I don’t have any information on if this skill helps while inside the rift boss worlds.

The in game help reads:

Skill duration: random.
Type of skill : automatic skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
This skill will allow an explorer of a rift world to resist its inhospitable
environment for a longer period of time.

This is the cast type skill for rift spells.

The in game help reads:

Skill duration: random.
Type of skill : spell casting skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
This skill lays the groundwork for all spells which manipulate cross-dimensional
energies, and beings. Even the most accomplished Riftwalker does not disregard
the knowledge gained from these simple, but foundation-forming abilities. The
guild has a saying "Disregard the simple, and simple you shall remain".

This is the cast type skill for protection spells.

The in game help reads:

Skill duration: random.
Type of skill : spell casting skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
Many users of magic who had studied the offensive 
natures of magic, found that magic of a defensive nature
was just as useful. There isn't much that can stand up
to sheer power of offensive magic, except perhaps magic
itself. There are many spells which deflect, or help
one avoid the affects of spell cast upon them. This type
of spell requires a certain knowledge of magic and its
protective nature. Being skilled in this knowledge can
make a caster of protective magic much more capable.

This is the cast type skill for healing spells.

The in game help reads:

Skill duration: random.
Type of skill : spell casting skill (arcane skill).
Affecting stats: None.
It uses no endurance points.
One of the more benevolant types of magic, is the
magic which is used to heal one's self or others.
Not many things, once killed, are of any use to
anyone, so keeping things alive was one of the first
forms of magic that was utilized. Originally starting
as witch-doctors in various tribes, the art of healing
through magic has evolved to a very refined art. No
town within the realms is without a local healer.
It is a very dangerous world, so the art of healing
has been practiced and refined through the ages.
In order to use healing magic effectively, some
knowledge of the nature of this type of magic is
required.