Dominion

Dominion is a highly advanced Extrinsic spell that allows the user to manipulate the ambient magic energy within the surrounding area to enhance their power while also minimizing their magic consumption.

Description
Every user of magic possesses a unique frequency for their magic known as their "magic signature". Akin to fingerprints, this signature can be used to identify the user of a magic spell by analyzing the remnants of a spell or the trace amounts of one left in the environment. Through the arduous task of attuning their own magic signature to match that of the environment's frequency, the user can assimilate their own magic with the surrounding area's ambient magic and take control of it, funnelling it into their spells, thereby creating their own Dominion.

By allowing the user to use the tremendous amount of natural magic within the local area instead of their own, a user's Dominion essentially allows them to use more magic than they would be able to normally. Offensively, the user can funnel the magic into their own spells to increase their power, effect, and range, and launch attacks in any direction and from any direction within the zone. Defensively, the user's defensive spells' size, coverage, and durability are also augmented. The user could even prevent the targets within the Dominion from gaining magic by forcing the magic near them away, and trapping them within the area by erecting magic barriers near the edges of their Dominion. The closer the user's own magic frequency is to the natural frequency, the more magic they can access around them, effectively increasing their power and range.

Additionally, this Extrinsic also allows the user to minimize their own magic consumption since they are utilizing the surrounding area's magic instead of their own. As a result, as long as their Dominion is maintained, the user never runs out of magic to use for their spells. This makes setting up a Dominion the trump card in a battle of attrition.

Due to the sheer amount of training one must undergo to learn this technique, as well as the additional training needed to practically use, refine and eventually master it, Dominion is a technique not many in the world are willing to devote themselves into learning. Additionally, in the case that a user's Dominion dissolves either due to failure of maintaining it or even voluntarily, their own magic that is used to catalyze the Dominion's formation cannot be regained and is lost to the surrounding area, rendering them temporarily magic-less, making the technique high-reward yet high-risk.

Countermeasures
Maintaining a Dominion is incredibly taxing, as the user must constantly keep their magic signature closely attuned the environmental frequency. Even the slightest deviation could result in decreased power and range of effect for the user's Dominion. During battle, this task becomes increasingly difficult as the user would have to split their focus between maintenance and combat. As a result, by breaking the user's concentration on maintaining their Dominion, one can temporarily destablize the Extrinsic and halt its effects, giving them a chance to either flee or counterattack.

While it is considered impractical in the midst of battle, the target of a Dominion could attempt to establish their own Dominion and enter a power struggle with their opponent's. Since the more closely a user's magic is attuned to the natural frequency of magic, the more control they have over the environment's magic, the user whose magic signature synchronizes with the natural frequency the most would win the power struggle and destroy the other's Dominion.

In the unlikely case that their opponent did not create a barrier that prevents the user from escaping from the Dominion's area of effect, the user can simply move away from their enemy to defend themselves against a Dominion. However, as the user usually acts as the epicenter of the Dominion, this countermeasure can be overcome if the enemy is faster and chooses to pursue them.

Pseudo-Dominion
With enough magic, users with exceptionally high magic reserves can create a Pseudo-Dominion. By overflowing the local area with their own magic and pushing out the natural magic energy, the user can achieve an effect similar to Dominion. However, while this technique allows the user to attack from any direction within the zone, it does not provide any other benefits accessible through true Dominions, such as the increased magic power and decreased magic consumption. While a Pseudo-Dominion is considerably easier to maintain than a normal Dominion since the user does not need to change their magic signature, it is incredibly taxing on the user's magic and can quickly exhaust the user.