Magical Nexuses

Magical Nexuses

A magical nexus, also called Leyline, is a location on the material plane that has a strong connection to another plane, force of nature or type of energy. This may be a structure, such as an obelisk, but most often this is a region. The strength of the connection varies from area to area. It may be a weak connection, doing little more than drawing certain creatures to its location, or it may be a strong planar connection where spellcasting is enhanced and even portals to other planes open naturally.
While near the region or object of power, a spellcaster can make a spellcasting ability check (DC varies) to notice they are in a region where a specific type is enhanced. The spellcasting check may vary by type and are listed below.
The actual powers and effects of these nexus's vary even more widely than the types themselves, and are up to the DM to determine the specifics. Some areas may have multiple types in them, and this could yield unique results. Players may attempt magical research while in this areas, or to even attempt to perform acts or feats beyond the original casting of the spell by making a spellcasting check.
For example, while in an area of Law, a druid attempting to Conjure Animals might make a check to instead call upon a Bronze Dragon Wyrmling, as this is a Lawful creature and appropriate CR. If this was a particularly powerful area, it could even be a more powerful creature than normally allowed such as a Gold Dragon Wyrmling. This is simply one example, the specific spell, plane and nexus will require the player and DM to be creative with the possibilities.

Types of Magical Nexus

These are the most common types of magical nexus that are found throughout the world, though others types than are listed here may be found.
Law (arcana) - The forces of law are strongly represented in this area. Smooth lines, rigid adherence to order and familiarity in all respects can be found here. Plants grow naturally in rows, creatures tend to behave more as a group rather than individuals, and attempts at spreading chaos are curbed. This could be an area where Celestials or Devils are easier to summon, that has a boon to mechanical engineering or tinkering, or some other benefit to Law. The forces of chaos find themselves repulsed from the area and randomness is not found.
Chaos (arcana) - The forces of chaos are strongly represented in this area. Vast caves systems, with no concern nor method of structure are found here. Plants grow wildly, creatures of all variety are found within the area, and attempts at taming or controlling the region are suppressed. This could be an area where demons are easier to summon, or where creatures such as Orcs, Gnolls and Bugbears find themselves at home.
Good (religion)- This area is infused with the blessing of good, often from a good aligned deity. It could be the location of a long-standing bastion of good, or where a humanoid ascended to demi-god status, or some act of heroism was performed. It might be easier to summon celestials, communicate with a good deity, cast healing spells or some other boon to perform good works. Evil may wish to taint areas of good and corrupt them, but may find it difficult to overcome the inherent positive focus this area has. It might have a connection to the positive energy plane, or some other benefit to radiant energy. This area may cause those corrupted by evil forces to see the error in their ways, and be more likely to seek redemption.
Evil (religion)- This is an are where particularly wicked deeds have been committed and the very land is tainted with evil. Often this desecration is commanded by an evil deity. It might be easier to summon undead, fiends or to cast otherwise wicked spells while within the area. Good may wish to cleanse this land of its evil taint, but may find the deep seated nature of its corruption difficult to root out. This area may cause depravity and corruption in those that spend too long in the area, and even the strongest of wills to decay into depravity and evil.
Magic (Abjuration, Conjuration, Divination, Enchantment, Evocation, Illusion, Necromancy, Transmutation) (arcana)- These areas are particularly attuned to a specific school of magic. You may find that area of magic easier to cast, while others may be suppressed. You may find that your type of magic has certain boons, takes less spell slots or otherwise has some sort of connection. The area may also cause strange effects
Elemental (Cold, Fire, Earth, Air) (arcana/nature)- These nexus are linked to the elemental planes, and the magic of their element flows through this region. It may result in having creatures tied to those planes being easier to summon or even found in the wild, magic of that elemental type being more pronounced, or some other boon to that element. It may result in that type of energy being pronounced in a region that would otherwise not allow it, such as a region of frigid cold in the middle of a scorching desert.
Feywild (arcana/nature)- This region has a particular connection to the Feywild. It may open portals to the feywild or cause oddities where turning a corner finds one in the other plane. Plants grow much more wildly in this area, and the seasons can be more attuned to the effects of the feywild than the normal weather for the region.
Shadowfell (arcana) - The regions boundaries to the Shadowfell are particularly weak. This could result in the planes being able to affect each other across planar boundaries, or even stepping from one plane to another without realizing it. Color in this region is often suppressed and the affects of daylight can be weak. In some particularly strong areas, daylight may be completely dampened to the point where creatures such as Vampires can exist even in the broad daylight. For this reason these regions are considered particularly dangerous. Shadow energy and areas of shadow may bleed into the material plane, causing strange effects such as twisting of trees, warping of magic and distortion of perception. It could even infuse mortals who live in the area with the essence of shadow stuff, potentially turning them into shades.