The Aetherstator is a formidable 30mm semi-automatic cannon, designed by the Salvatians, a race of neohumanity & neotypes, in a sci-fi era where the boundaries between magic and science have been entirely dissolved. 

Drawing inspiration from the Harkonnen II, an unique weapon from different universe identified as Hellsing Ultimate, the Salvatians have pushed the design further, infusing it with their unique blend of arcane mastery and advanced engineering. The Aetherstator features a sleek, elongated barrel crafted from darkened, rune-inscribed metal, which channels arcane energy into each shot, vastly increasing its destructive capabilities. 

The dual giant-size ammunition backpack is a critical component for any infantry soldier wielding the Aetherstator semi-automatic cannon. Designed with both functionality and durability in mind, this backpack ensures that the user can sustain prolonged engagements on the battlefield without the need for constant resupply. The backpack is massive in size, constructed from reinforced, lightweight composite materials that balance durability with ease of movement. It can hold up to 200 rounds of the specialized 30mm arcane-bolter ammunition, each securely housed in individual slots that prevent jostling and accidental discharge. 

It is equipped with a highly efficient, automated feed system that seamlessly transfers rounds from the storage unit to the Aetherstator via a reinforced, flexible conduit. This conduit is embedded with arcane sigils that maintain the integrity of the rounds during transfer, ensuring that each shot is fully charged with both kinetic and arcane energy by the time it reaches the chamber. In addition to holding physical rounds, the backpack also contains an integrated arcane energy reservoir. This reservoir is linked directly to the Aetherstator, providing a continuous supply of arcane power to enhance each shot. The energy is drawn from the surrounding environment, using a network of arcane runes to siphon ambient magical energy, making the backpack partially self-sustaining during combat.

Despite its size and weight, the backpack is designed for comfort and stability. It includes a custom harness system that distributes the weight evenly across the user's back and shoulders, minimizing fatigue. The harness is adjustable and features shock-absorbing elements that reduce the impact of movement and recoil on the user's body.

 In the event of an emergency, the backpack is equipped with a quick-release mechanism that allows the user to detach it rapidly. This feature is crucial in situations where mobility is more important than sustained firepower, or if the backpack becomes compromised during battle.

To protect both the user and the ammunition, the backpack is lined with a layer of arcane shielding. This shield prevents external magical forces from tampering with the rounds or the energy reservoir, ensuring that the weapon remains operational even in environments saturated with hostile magic. It's designed to function in a variety of environments, from the vacuum of space to the depths of a jungle. It is sealed against dust, moisture, and extreme temperatures, and includes an integrated cooling system to prevent overheating during extended firefights.

This weapon is not merely a tool of war but a symbol of the Salvatians' dominance over both the natural and supernatural realms, capable of tearing through both physical and magical defenses alike. Its ammunition, a combination of arcane energy and bolter rounds, is a technological marvel on its own; each shell is engraved with intricate sigils that store and release arcane energy upon impact.  Built to withstand the harshest conditions, the backpack is resistant to explosions, impacts, and energy attacks. The outer shell is composed of a multi-layered composite that can absorb and deflect damage, ensuring that the precious ammunition inside remains safe and ready to use.

When fired, the Aetherstator releases a pulse of raw arcane force that not only pierces through armor but also disrupts the very essence of its target, causing catastrophic damage. The weapon's semi-automatic firing mechanism allows it to unleash a rapid succession of these devastating rounds, overwhelming even the most resilient of foes. The recoil is immense, but the weapon's advanced stabilizers, powered by arcane runes, make it manageable for a trained wielder, turning them into a one-person army. 

The Aetherstator's design includes a modular framework, allowing for the attachment of various enhancements, such as arcane focusing lenses or additional energy reservoirs, further increasing its versatility in battle. Despite its size and power, the Aetherstator is surprisingly portable, with a collapsible stock and a custom carrying harness that distributes its weight evenly. 

The weapon is highly sought after by soldiers and mecha fighters, each drawn to its blend of ancient power and cutting-edge technology. In the hands of a skilled user, the Aetherstator becomes more than just a cannon; it is a harbinger of destruction, capable of turning the tide of any battle in favor of the Salvatians.

Infantry:

Penetration Power: The Aetherstator's 30mm shells can easily penetrate standard infantry armor, even those reinforced with energy shields or magical barriers. The combination of arcane energy and bolter rounds ensures that each shot not only pierces physical armor but also disrupts the target's internal structure, causing severe internal damage or instant disintegration.

Area of Effect: The arcane energy released upon impact creates a shockwave that affects a small radius around the impact point, making the weapon effective against tightly packed infantry formations. This secondary effect can incapacitate or kill nearby soldiers even if they are not directly hit by the round.

Anti-Magic Capabilities: The weapon's arcane disruption makes it particularly effective against infantry that relies on magic for protection, nullifying spells and barriers before they can fully form.

Mecha Fighter:

Armor Penetration: The Aetherstator's shells are designed to penetrate the thick armor of mecha fighters, similar in design to mobile suits from the Gundam series. The combination of kinetic force from the bolter round and the arcane energy burst ensures that the round can breach even the most advanced armor plating.

Critical System Disruption: Upon penetration, the arcane energy disrupts the mecha's internal systems, causing malfunctions or complete shutdowns. This is particularly devastating against mechas that rely on complex electronics or magical systems for operation.

Versatility: The weapon's modular design allows for the use of specialized ammunition types that can be tailored to different types of mecha armor, ensuring effectiveness against a wide range of enemy units.

Range: The Aetherstator has a long effective range, allowing it to engage mecha fighters from a distance, where its powerful rounds can punch through their armor before they can close in on the operator.

[For added note, you know they say: "B*tches loves cannon" - Hellsing Ultimate abridged]

Here is an example:

https://youtu.be/snf7tTghkOw