Empyrean Magent

Magent isn't a word very commonly used by anyone in the empire, but amongst the mages of the Wizarding Academy of Empyrean Prime, there are a small subset of specially trained warriors who bear the official title of Mage Agent. Over time, these soldiers had their title reduced into the shorthand term "Magent," and while very few people outside of the Academy even know about these special warriors, their training makes them a unique and different breed than almost any other type of fighter. These protectors learn to resist some spells better than others, learn to gain additional benefit from some types of spells being cast upon them, and can even assume the concentration on some spells cast on them, freeing up their mage ally's mind for more powerful spells.

Magent Training
Beginning when you choose this archetype at 3rd level, you gain training in important skills that help you in assisting wizards on the battlefield with magical tools. You are able to use magic items that require spellcasting to use as long as the spellcasting or spells required could be satisfied by the wizard spell list, or by your current fighter levels as if you were a wizard. For example, you could use an item the requires you to be able to cast Fireball if you are 5th level in this class, but an item that requires a spell not on the wizard spell list is unusable. Also you may attune magic items as if you were a wizard of your fighter level. Intelligence is your spellcasting ability for any spell cast using these items.

Magical Inurement

When you choose this archetype at 3rd level, you become trained in the techniques that allow you to defend yourself against the most common magical onslaughts. Whenever you become the target of a spell that causes you to make a Dexterity saving throw, you add your proficiency bonus to that saving throw. You also have advantage on saving throws against spells that would cause the charmed or frightened conditions.

Additionally, if a friendly creature within 5 feet of you would be the target of a spell attack roll, you may use your reaction to become the target of that spell instead.

Shared Focus

At 7th level, you learn perhaps the most important skill in the Magent's arsenal: the Shared Focus Bond. This telepathic bond not only enables communication with an ally, but also allows you to assume the burden of concentrating on some spells. As an action, choose a friendly creature within 5 feet of you to begin the bond. You become able to telepathically communicate with that creature out to a range of 90 feet, as long as you both share a language to communicate. Additionally, if the creature in the bond casts a spell of 3rd level or lower that requires concentration, you may use your reaction to assume control of that concentration as if you had cast the spell. The bonded creature no longer needs to keep concentration on the spell, but in all other ways, the spell is treated as if the spellcaster were concentrating on it for as long as you maintain this concentration. You cannot maintain concentration on this aspect of the bond and on a spell that you cast, and if you cast a spell that requires concentration, the concentration assumed by the bond ends normally. This bond lasts for a number of hours equal to your proficiency bonus and may be used twice before you must finish a long rest to use it again.

Additionally, if you are the target of a spell that you have assumed concentration on using this feature, it creates a positive mystical synergy which grants you a +2 bonus to your saving throws while you maintain this concentration.

Arcane Conduit

At 10th level, your special training and meditations have opened your aura to being extremely receptive of beneficial magical energies, turning you into the most efficient conduit of those energies. If a spell cast on you from a friendly creature would either restore your hit points or bestow temporary hit points upon you, and that spell would use a die roll to determine the hit points gained, you gain the maximum amount possible for each die instead.

Additionally, if the target of your Shared Focus Bond casts a spell that targets only themselves, you may use your reaction to also receive the benefits of that spell, but if that spell requires concentration, you must also maintain concentration to receive this benefit. If either your or the creature in the Shared Focus's concentration fails, you lose this benefit.

Aura Reservoir

At 15th level, your Shared Focus Bond improves so that you may develop magical reservoirs shared in your aura for extra castings of magical spells. As an action while your Shared Focus is active while the target of your bond is within 5 feet, the target of your bond may expend a casting of a spell they have prepared and are able to cast and place the spell energy in an aura reservoir. For as long as the bond remains active, either they or you may cast that spell from the reservoir. If you cast this spell, you cast it as if you were a wizard of your fighter level, using your Intelligence as the spellcasting ability for that spell. You may not cast spells from the reservoir if they are of a higher spell level than a wizard equal to your fighter level could normally cast. A maximum of three such spells may be stored in the bond's reservoir at any time. When your Shared Focus ends, if there are spells within the aura reservoir, they disappear with no effect.

Arcane Smite

Beginning at 18th level, you are now able to weaponize the magical energy you receive into powerful magical weapon strikes. If you are under the effect of a spell, or if there are spells in your aura reservoir, you can end the spell on yourself, or use the spell cast into the aura reservoir to empower an Arcane Smite. When you hit with a weapon attack with a magic weapon, you may end the spell effect on yourself (as if you chose to end the duration or you successfully dispelled it from yourself) or expend a spell from your aura reservoir and add 1d8 force damage to the damage of that weapon strike for each spell level of the spell you end on yourself or the spell you expend.