World effects involve effects upon the natural world over and above what a natural man could be expected to perform. Generally none of these skills would be available in universes without magic, technology akin to magic, supernatural elements, or superhuman powers, so taking any of these skills would be per the GMs judgment.

Although these powers may be used as attacks in many cases, they aren't generally used simply as mechanisms for damaging an opponent. Instead they are ways of subverting natural laws and the laws of physics to better deal with the dangers of the world and accomplish the purposes of a particular campaign.

Creating light in the dark, adversely affecting the undead, thrusting a battlefield into chaotic darkness, creating circumstances favorable to blindfighters, hiding in shadows, and other stealthy activities are all within the abilities of a character skilled in light and darkness.

Characters with this ability can see in the dark without aid and are not affected by sudden changes between light and darkness, both of these abilities without the use of mana. Imbuing this ability on others, however, would however require the use of mana appropriate to the degree being affected.

Races with a weakness to light are affected as if this is a standard damage roll, and because this generally affects a weakness, the defenders often get no defending dice unless they manage to find something in the environment to obstruct the direct line of the light.

Light is not limited to white light. Any color within the light spectrum, which is to say all of them besides black, can be created with this power, and characters with this skill often have an affinity for a certain color over all others.

The sound skill involves the creating of sound as well as the absence of sound. It ranges to anything from modifying conversations to creating deafening claps of thunder and from totally removing any sound to allow a party to pass undetected to amplifying nearby sounds sound the character can understand them. But a player shouldn't be limited to just these effects. Anything related to sound should be possible to a character with this skill.

Like most skills, the general rules apply, so there's only a limited amount that a first skill degree user can do, usually involving limiting or enhancing sound on his immediate person.

At later degrees, however, much more can be accomplished.

When conversations are modified, only a successful skill check is required unless there is some reasonable reason why an opponent might notice the change, such as reading lips and seeing the words don't match. In such cases, the Win-Loss check would be made against Reading Others.

Thunder claps can cause dice of bludgeoning damage equal to the standard damage roll, and have the additional effect of deafening opponents with more losses than wins when treated as a Win-Loss check. Thunderclaps require the ability to affect an area, so higher degrees are required for this and similar effects.

Skill over space includes the ability to interact with other planes and dimensions including summoning from those planes (if the caster also has the summoning skill), teleporting, creating and navigating wormholes, creating pocket dimensions for storing things, and other abilities. The mana cost is per person or affected area and maintaining the effect costs a passive action as well as additional mana per person or affected area. Because of the dangers inherent in the use of this skill, rolling no successes should cause something unwanted and dangerous, perhaps even life-threatening, to happen.

Skill over time includes the ability to hasten or slow oneself or others in comparison to the real flow of time or to view a place at a specific instant of time, if that time is known.

Slowing and speeding up time is available to first degree users, increasing or decreasing the number of actions (relative to others) by one action per degree and costing one mana per opponent affected. Such effects, if used often however, have been known to abnormally age the creature affected.

Because it is so difficult, stopping time requires a fourth degree user at at least four successes on a standard skill check.

Reversing time requires a sixth degree user and requires at least six successes on a standard skill check. Even with a success, it is extremely dangerous because it can cause paradoxes with effects only the GM could know. When used in conjunction with illusion abilities, this particular ability could be advantageous for reconstructing a crime scene in such a way that the character and others can figure out what happened, but it would require the skill of time with an area of effect element.

Because of the dangers inherent in the use of this skill, rolling no successes should cause something unwanted and dangerous, perhaps even life-threatening, to happen.