After 4 years being a baron, the empire that you are sharing a border with decides to declare war to your suzerain. It will take at least a year for them to muster their whole army and knock on the doors. You, the Baron has one year to prepare for war.
The rest of the country refuses to help you due to the elitism of country's nobility. The royal family can't help you without showing favoritism and tells you that this is a trial on how well you handle the situation. Furthermore, the nobility have decided to protect the second line of defense instead of your barony. The nobility sees you as a social climber who knows nothing and they prefer to leave you to the enemy. They see this as an occasion where you can prove yourself (how useful you can be). They will barely supply you with anything but trading activities remain open.
Your task is to delay the enemy at all cost since the country has little knowledge of war logistic. but no one said you cant stop them.
The adversary, the empire, is a regional dominant power that can muster more than a million professional soldiers of its own, 4 million levies and another 2 million mixed of professional and levy soldiers from its vast vassal states. Economy wise, they can maintain a standing army indefinitely. They also deploy land battleships with no gunpowder but with numerous ballistas and formidable magicians that serves as the battleship's main weapon. The empire is not festered by corruption and uses divide and conquer tactics to subjugate adversaries.
The baron's country is protected by mountain ranges and known for its formidable and numerous dragon knights, wyvern riders and griffin knights. The country also has many magic knight orders and a well equipped professional army of 100,000 with an additional 400,000 levy that can be called upon but the levies are very poorly equipped. They also possess the most talented magicians in the continent and are prepared to go to war at a moment's notice. Not that they will count by they must be considered to the decision as it might be, sooner or later they might be your enemies. THey are very much united under the current royal family and can't be bribed by anything.
The design objective
You have a year to prepare but the snowy winter will last for 2 months at least, which will impede your preparation for war.
You have to design something that will stop the enemy on its tracks, deter them from invading. Or if anything fails, destroy the invading army. However, if you totally destroy the invading army, the other foreign powers might seize this moment of weakness to attack. You need to sink the empire's army morale to stop them in their tracks when by using your deterrent.
Unfortunately you don't have reputation enough to scare the enemy.
But you have a resource that no one has, you are from modern day Earth.
Using that resource to full strength you realize that "Peace through Superior Firepower" fits your taste and need as diplomatic approach will either tell you to die or betray.
You come up with 3 designs of weapons that can be used as deterrent.
A flying ship or an airship - You've been constructing one for over a year ever since you have discovered how to make it float! But the workforce is not skilled enough to construct this wonder in time unless you dedicate all your resources there. You will need at least two for a complete military effectiveness or so you think. Logistics and maintenance of this will be very troublesome but it will be worth the trouble.
A Super-Gun - You know how gun works, you have mass produced it for your standing forces. The thing is, how to make a gun or in this case cannon scary enough for any threats/diplomatic relations that they'll be thinking twice before knocking on your doors again. You have a dwarven clan from the mountains that will work for you to create this cannon, but still unless you concentrate your resources on this work, it will not be completed before the war. Not to mention that you haven't tested the design and you are not even sure that you have enough resources to maintain it.
Prism tower Spellarms - Your fortress has the tallest tower in the known world. You can see everything in the horizon, including the invading army and the nobility army. You can cover your front, rear and flanks with these spellarms. But you've just begun studying runecrafting effect for light. You don't know how to weaponize light but you have the power issue solved because you still have a tortoise behemoth heart that you got from your adventure. You are confident that you can weaponize light but the question is will you be able to weaponize it before the imperial army knocks on your doors? To top it off it is only limited to your territory alone.
Food - You have plenty. You also have several refrigerated and vacuum warehouses: you can withstand a siege of few years, give or take.
Mineral - You have a lot since your territory is surrounded by mountains: gold, silver, copper, brass, iron and other metals. Not to mention, the discovery of an all temperature super conductor and crystalline metal that when heated makes things float. You are definitely loaded with resources but you don't have enough people to utilize the output of your mines/foundry to full effect.
Manpower - due to abundant food and work, many peasants have been relocated to your barony. However they are not enough to start your wartime manufacturing without suffering the consequences in few weeks. You have dwarven mountain clans that resides in your territory that can be coerced to work for your projects, but you need to focus on one project alone due to manpower constraints. In addition you have bought slaves to supplement your lack of manpower.
Army - You have an army of 7000 mixed troops ranging from gunpowder troops which numbers 3000, 2000 troops of well armored militia which was thought of team work and 1000 troops of skirmishers that uses lever action crossbows. Additionally, you have 1000 troops for 227 mixed battery of mortars, howitzers and cannons. These troops are better equipped than both king/queendom and imperial elite soldiers. Their morale is high and they know how to follow orders. However against the empire's million army, they probably will count for something but not victory. You simply don't have enough body to throw at the imperial army even if you enlist all of your people.
Weapons and armor - With the introduction of gunpowder weaponry, you are bound to be superior to anything you face except numbers. The introduction of new ways of manufacturing steels and other refined metals, the ease of manufacturing armor, weapons and other war and industrial components allowed you to deploy a professional army. Your weapons are better, sharper and harder than anyone in the world except spell arms and of course your gun powder weaponry, your armor is lighter, stronger and easy to procure allowing you to deploy armored troops, remotely detonated mines that can be deployed in preparation for any conflict. and lastly, your artillery batteries that allows you to pound enemies at extreme ranges with good to acceptable accuracy.
Magician - Just one and her main magic strength lies in healing, alchemy and runecrafting.
Yourself - you can use magic, which is limited to time-space manipulation, rune crafting and spellarms. To top it off you are a very rare male magician albeit weak but with very rare magic.
Various UAV - You have brought things from modern Earth. One of it are surveillance UAV. It will be very useful for real time intel gathering and leading artillery fire to the right place at the right time.
Your pet tyrannosaurus rex - She is intelligent short of making conversations with you. she is as big as a house and loves you like her mother.
Tri-Heart of Behemoth Tortoise - The still beating heart of a titanic monster you faced. Capable of generating huge amounts of mana indefinitely.
Shells of Behemoth Tortoise - The shell of the Tortoise you have slain a while ago. Amazingly stronger than any thing you know and super magic resistant than dragon scales.
Bones of Behemoth Tortoise - Surprisingly soft and brittle but has many uses apart from potion ingredients like can be used to ultra focus glass and make it stronger, mixed with metal to be very heat and kinetic resistant and when mixed with mercury, can be a deadly odorless aerosol.
A very large diamond - The size of a lion head. Your magician said that a very small diamond the size of a child's nail is capable of storing huge amounts of energy.
Dragon Heart - A still beating dragon heart that you manage to acquire after killing your first dragon. You realize that the mana that this heart pumps can be converted to electricity.
With the resources you have, you must achieve the following from any of the 3 designs.
- Deter ANYONE from threatening your position
- Be able to do the "Speak softly, carry the big stick" diplomatic approach
- Stop the imperial army on their tracks without totally decimating them
- prove your usefulness to the royal family.
- Not be threatened by the elite nobility of the kingdom
- positive future prospect in terms of economy, military and politics for your territory.
Which of the three designs will be the best deterrent?