The Sentry represents a new breed of tactical fighter who has mastered the art of nanomachine warfare. Rather than relying solely on personal combat prowess, these fighters deploy sophisticated autonomous constructs to control the battlefield. Through a combination of advanced engineering knowledge and intuitive battlefield awareness, Sentries create deadly zones of crossfire and provide unparalleled tactical support to their allies.

A Sentry's most distinctive feature is its M.A.D.S. (Mentally Aligned Deployable Sentry) - a small but deadly nanomachine construct that serves as an extension of the fighter's will. These devices can be rapidly deployed, reconfigured on the fly, and upgraded with specialized modules to adapt to any combat situation. Whether providing suppressive fire, defending allies, or revealing hidden threats, the M.A.D.S transforms any Sentry into a force multiplier on the battlefield.

Masters of tactical positioning and area denial, Sentries excel at controlling engagement ranges and dictating the flow of combat. Their intelligence-based approach to warfare allows them to outthink opponents rather than simply overpower them. At the pinnacle of their abilities, a Sentry and their M.A.D.S function as a seamless unit, capable of engaging multiple threats simultaneously while providing comprehensive battlefield support to their entire team.

Level 3: Deploying M.A.D.S

M.A.D.S. (Mentally Aligned Deployable Sentry) You learn how to craft autonomous nanomachine sentries linked to your mind, and use them as dependable turrets to rain down fire upon encroaching enemies.

M.A.D.S. are objects.
- As such, they are immune to poison and psychic damage.
- They have a number of HP equal to your Fighter level × (your Int modifier + your Prof bonus).
- Their AC is equal to 10 + your Int modifier + your Prof bonus.
- If it is forced to make an ability check or a saving throw, treat all its ability scores as 10 (+0).
- As a utility action, they can be deployed in an unoccupied space within 5ft of you.
- When you deploy a MADS, pick a ranged weapon you have on your person. That weapon is installed in the MADS.
- You can retrieve a MADS that doesn't have 0 hit points as a utilize action if you are within 5ft of it. When you do so, the installed weapon is uninstalled.
- You can retrieve an installed weapon from a MADS with 0 hp.
- While linked to a MADS, the nanomachine link allows you to see through its visors, making perception and investigation checks from its position if you so decide.
Manual Mode:
When you are within 60ft of a MADS, you may make attacks with the installed weapon. If you do so:
- You make the attack(s) from the MADS' position.
- You ignore the reload and loading properties of the installed weapon, if any. You still need to have ammunition for the installed weapon.
- You use your intelligence modifier for the attack and damage rolls instead of Strength or Dexterity.
- You cannot add any additional bonuses to your attack or damage rolls.
MADS Setups:
When deploying a turret, pick a setup.
Once per turn, when a creature within the installed weapon's range triggers the setup you picked, you can make an attack with the installed weapon.

- Suppression Fire: a creature that moves within 120 ft of the MADS.

- Guardian Mode: a creature attacking an ally within 120 ft of the MADS.

- Hunter's Watch: the first creature using a spell on allies within 120 ft of the MADS.

- Ambush Point: the first creature that enters a specified area of max 20ft square within 120 ft from the MADS.

Level 7: Optimized Systems

Your MADS becomes more efficient and resilient through improved nanomachine programming.

- Critical Calibration: Attacks you make with the installed weapon score a critical hit on 19-20 (improves to 18–20 at level 15).

- Shared Vital Surge: When using your Second Wind, the M.A.D.S. will recover the same number of HP you heal.

- Shared Martial Sense: You may now add additional bonuses to the attack and damage rolls you make with the installed weapon.

Expert Technician:

- You can deploy or retrieve a MADS with a bonus action instead.

Level 10: M.A.D.S. Upgrades

When you craft a MADS, you can install specialized modules in it. If you do so, the cost of the components used in crafting that MADS increases by 1000gp, and you spend four hours working on it as part of a long rest or during the day.

If a MADS with a specialized module has 0 hit points, it cannot regain hit points by any means.

You may install different upgrades on different sentries on your person, taking into consideration that they need to be linked to function properly.

- Flight Core: You can deploy a MADS with this module in an unoccupied space within 30ft of you. Once per turn, you can move the MADS up to 30 feet in any direction (including upward). It can hover, and when you move, it will follow your movements while maintaining its position relative to you.

- Nanomachines Cloud: Some of the nanomachines of the turret are to disperse in a cloud surrounding it: allies within 15ft of a turret with this module gain the benefits of half cover.

- Scanner Protocol: Your MADS emits a bright light in a 30-foot radius and a dim light for an additional 30 feet. This special light reveals invisible creatures and illusions within its light range. This lasts as long as it is deployed.

- Self Repair: A deployed MADS with this module regains hit points equal to 2 x (your proficiency bonus + your intelligence modifier). If the MADS takes lightning damage, this feature does not function until the next round.

Level 15: Reformation

Your nanomachine mastery allows you to initiate an emergency protocol to reconstitute a destroyed MADS, at a cost.

- When the M.A.D.S. is reconstituted with this Utilize action, it will regain half of its maximum hit points and reconstitute the link. This will deeply damage the structure of the turret, which will lose 10 hp at the end of each of your turns, or until dismissed. Once per long rest.

You can reconstitute a MADS once after a long rest.

- Attacks made with the installed weapon now score a critical hit on a roll of 18 to 20.

Level 18: Cerberus Protocol

Your mastery of nanomachines reaches its peak.

- As a utility action, you may activate the Cerberus Protocol: this will overload your currently active turret, causing it to upgrade itself instantly.

- It will gain the benefits of all specialized modules at once.

- Any number of setup attacks per turn.

- This protocol lasts for 10 minutes. After the ten minutes are up, the MADS will be automatically dismissed.

- Once used, you cannot use this feature again until you finish a long rest.