A superhuman character only damaged by a nuclear blast’s fireball. What other modern or near future weapon could damage them?

First time asking question here, trying to gauge the character power ceiling for my worldbuilding.

It’s a science fantasy world featuring a Magic and Technology faction at war. It is envisioned as a Real-Time Strategy game: think of the two factions as Protoss and Terran but at a terrestrial level. The Technology faction is roughly like a modern military with some near future weaponry enabled by limited magitek, such as satellite lasers. The Magic faction resembles typical high fantasy world, but their individual power ceiling can be physics-defyingly high. However I still want to be accurate about physics whenever possible (one of the goals is to put standard fantasy elements in a hard scifi-like setting and see how they interact with things)

The character in question has a human appearance, and is almost impervious to harm to anything less than being inside a nuclear blast’s fireball. Their defense mainly consisting of enhanced body and a magic barrier that deflects or absorbs attacks. The nuke I am considering is a 5 kiloton surface blast. According to [Nukemap][1] the fireball would have a radius of 168m. I did some calculations and estimated the energy flux received by this character at this distance to be on the order of 10^8 J/m^2. Now ordinary matter are said to be effectively vaporized at this distance, but this character is just starting to get serious burns (which they can naturally heal from over time) and the shock would break some of their bones, but not yet enough to remove combat capabilities. The radiation at this distance also destroys some of their cells, but they can also recover from it given time.

Since this is an RTS game this character is going to be a hero unit that is engaging hordes of infantry/tanks while being bombarded with airstrikes. The question is however, whether any conventional weapon would even be able to hurt them, and if so, what weapons?

War and battle are more than just killing enemy soldiers. There's targets and objectives, there's logistics and intelligence. A single soldier that is for all practical purposes unkillable can still be rendered ineffective.

Non-lethal tools would still be effective. If the character is still human, then they still have human senses. Fog clouds, bright lights and loud sounds, toxic gasses, and difficult terrain would all render an unkillable soldier ineffective in combat.

An army of one is a myth. An unkillable soldier would still require support, like supplies of food and equipment and information on their own targets and objectives. Many heroes in fiction like Goku and Luffy are famous for their appetites that fuel their battle power, so cutting off their supplies eliminates them from combat. Also, destroying their means of communication so they don't know where the battle even is would be just as effective as killing them.

Just put them in a cage. If your super soldier is actually immortal then trapping and imprisonment would be the most effective strategy, such as when Angel was tied up on the ocean floor. Even more tactical measures like pit traps and snares would be much more useful and practical than trying to supply enough superweapons to try to kill them outright.

Humans have relationships and emotions. You could always go the Superman route and target the people around the hero. Your super soldier is likely going to be part of a squad that isn't as invulnerable, and if they have to spend all of their time shielding their comrades then they can't be completing their own objectives. They probably also have family and loved ones that can be held hostage to get the hero to stand down.

Make them not want to fight. Diplomacy and espionage can be used to turn the country against a person who is likely to be famous at home and abroad. Spreading rumors and lies about the soldier can mean that after the war they have nowhere to go home to. Lying to them about why they're fighting or who they're fighting for can make them disheartened and disillusioned. Even better is revealing terrible truths that were being kept from them. Basically this is targeting their morale.

These all become even more likely after your unkillable hero has demonstrated themselves in combat and the enemy has a chance to adapt and plan for encountering them.

First Answer, from a Pure Gamer perspective - super units that can only be damaged by a specific weapon are annoying as fu...

This is a sort of Frame Challenge-ish answer to start with, but as an Avid Gamer - I find it incredibly annoying when there is a single unit that can only be damaged by a specific Weapon. It is cheap, it breaks the flow of the game, often causes the Player to waste resources trying to deal with it normally - so from that point of view, my first answer is: Dont do this, it is annoying as hell.

However

Having strengths and resistances against certain Damage types is a well established and interesting gameplay mechanic.

Imagine a game that incorporated the classic elements: Fire, Earth, Water, Air. There is like a bajillion games to choose from that use these.

Fire Creatures have immunity from Fire attacks (or take reduced damage) - but take critical damage from Water attacks.

There is nothing wrong with having your Hero unit have resistances to regular types of damage. In Dawn of War 2 (WH40K RTS type game) - there are different damage profiles (Piercing, Melee, Power Melee, Heavy Melee, Plasma etc.) - Most Hero types have resistance to Piercing and regular melee attacks (as these are typically the damage profile that most T1 units have access to) - as the Game progresses, you have access to units that deal different Damage profiles and can be rather effective against the Hero units.

Answer 2 - if you absolutely must have them practically immune from Damage, must they be immune from effects...

You ever been outside in a really howling storm - when the wind is blowing, the rain is pelting down etc. You arent taking any Damage in any sense (except being cold and miserable) - but trying to move around and do stuff - it is harder, you cant see, your clothing is soaking and restrictive etc. it SUCKS

and this is my second answer - (and I would still recommend having them take some small amount of damage from regular attacks) - have it so that attacks still do something - such as slowing down movement, decreasing attack speed, increasing ability cool-down etc.

This way, you introduce counter-play options against your Hero Unit until you have built or acquired the super weapon to deal with your hero unit.

A drop of water in a stone is ineffective. If you drop a thousand nothing seems to have happened. Come back a thousand years later and the stone can be worn down. Damage is always there, however insignificant it seems. Now we need to figure out if you have enough.

You want to approach at least 10^8 J/m². The thing is that a nuke is horribly inefficient in transferring energy, just like any general explosion. The energy goes into all directions, having only a teensy bit of energy hit the target. The energy transferred is still immense, yet it still offers a way to do as much damage as a nuclear explosion without the massive fallout. Here some quick examples.

A shaped charge can at least have up to 10^11 J/m³. Now this is not my normal field of knowledge, but as far as I know we can transfer this to m² if we put the object right in front. If it spreads to 1m² it'll be 10^11 J/m². Much more than the nuclear explosion already. If we further focus down the explosion it'll rise pretty quickly.

Napalm is another. We can check the energy density if we burn it by approximating it to gasoline.. Around 44MJ/kg and around 737 kg/m³. Now apply a 0,5cm layer of napalm to the target over 1m². That burns with about 10^8 J/m².

Keep in mind that a 60kg person on a high heel will have around 5×10^6 J/m².

It is all about applying it in the right way. Many of the conventional explosives can still do some damage to your hero. Maybe even give a burn wound at the contact point. If we start talking about specialised explosives or attacks against this hero, it can turn out quite badly for them. With the right tools you can do more damage than a nuclear explosion, if you apply it in special ways on a tiny area.

Intuitively it can make sense. A rocket directly on a concrete pillar of 5m wide can reduce it to rubble. A 5kT nuclear explosion at 160m can crack the pillar, but generally doesn't reduce it to rubble.

At 1e8 J/m^2 a nuke can cause major burns and break bones, BUT most weapons don't attack the whole body at once. They hit a place on a target and concentrate the everything they have on that one place. Take a standard TOW anti-tank missile. It has a total explosive force of 1.5e6 J which sound like peanuts compared to your nuke, but it hits using a shaped charge that delivers about 2/3rd of that total energy into a 1cm^2 stream of plasma meaning that it actually hits with about 1e10 J/m^2 meaning that it will blow a hole clean through your hero with a similar damage profile as getting hit by a high calibre rifle.

Even with super regeneration, such weapons could be fatal. A head-shot will be enough to empty his skull of thinking meat meaning that even if he could regenerate the cells that make up his brain, there will be no lifetime of memories and experiences to draw on leaving the hero functionally brain dead. Alternatively, enough hits may cause him to bleed out making him pass out from blood loss even if his flesh can stich itself back together.

Beyond this, there are a wide range of anti-ship and bunker buster missiles that are way more potent than anti-tank missiles which hit with so much directed energy that a direct hit should realistically be able blast him into many pieces.

Treat a nuke as an area denial weapon for lighter forces, but against tanks or better, it should only be fatal if the target is fairly close to ground zero. You can further balance this by making them inaccurate enough to typically land outside of this anti-tank radius so that if you try to use it as a hero killer, it will probably not land close enough to get a 1-shot kill.

As for your Hero, you can basically give him a stat block similar to the tech faction's main battle tanks, but with rapid HP regeneration.

Antimatter

It would would work, if the setting allows for reasonable production rates and reasonable safe storage.

This fulfills the "power gauge" aspect: Antimatter can output an arbitrary amount of energy, even above nuclear.

Lasers

No laser can match the overall energy output of a nuclear blast. However, lasers can concentrate their energy into a tiny area, so they should be able to create small-but-deadly holes, right? Well, sort of; there are challenges:

Concentrating the laser is not as easy as it seems. Laser emitters convert 40% or more of their energy into heat, so if the laser beam is just narrow where it's generated, the emitter will get roughly the same amount of heat as the business end of the laser beam; the laser would destroy itself before it generated more energy than what a different energy source (like an explosive) could, so that's pointless. I know of two ways around that: (1) Use an array of laser emitters that are individually weak enough that they can fire long enough without overheating, and since lenses would eat too much energy and melt, use mirrors to concentrate the beams (X-ray imaging satellites use this technique, because there is no material that can act as a lens). (2) Use a free electron laser (which is not a laser, technically speaking, but it generates a coherent beam nonetheless). These already exist today, for creating ultra-short but ultra-high-energy laser pulses. I am not sure if this technology can be uses to deposit a lot of energy in a small area; "ultra-short" means it's a pretty mediocre amount of energy; you can ionize an ablate surfaces with that, but that's essentially it.

Weaponized lasers have another issue: they heat the air they are travelling through, which effectively creates a lens that disperses the beam. So you can't simply fire a beam at a distance - well, you can, but it will lose a lot of power on the way. So you shoot grenades that generate a laser beam on impact.

Nuclear-level energy densities don't merely heat air; they ionize it, creating a plasma. Plasma does not merely disperse the beam, it scatters them. As soon as a blob of air has been heated to ionization, it will create a blob that will absorb almost all energy, creating a fireball - a tiny one as the fireball size goes up with the total energy amount. I toyed with the idea of using a tandem shell, just like tandem RPGs work: The first charge creates a first hole, the second charge goes into that hole and makes it deeper. Unfortunately, this won't work: The second laser shell would have to go INTO the hole, and the shells need to be significantly wider than the hole because you need to concentrate the laser beams to avoid a self-destructing shell. What might work is blowing the plasma away. This is actually feasible, as the tip of the grenade is within millimeters of the contact surface and a small explosive charge can clear out anything gaseous/plasma-like really quickly. What actually happens is not a vacuum, but the clean-out gas simply moving faster than the laser can ionize it.

It's a pretty complicated kind of charge, but it does not generate radioactivity, so it might be preferred anyway. Besides, the millisecond accuracy that you need to ignite a plutonium bomb is breathtaking, and not easy to contruct either, so there's that.

This is a bit of a cheat, as it does not use more energy, it merely concentrates it better.

Thermobaric bombs

Now that requires the assumption that the "character" is essentially human and breathing. Thermobaric bombs have two lethal effects: Oxygen depletion, and lung rupture due to extremely steep pressure gradients over time.

So if the character needs oxygen to function, it will suffocate.

If the character has lung tissue, which by necessity needs to be fragile (otherwise there's not enough contact surface between lung tissue and air to ensure enough oxygen), a thermobaric bomb might be just enough to cause serious trouble, incapacitate, or kill - I think it's author's choice how robust that super-soldier's lung tissue is. In the end, he'll suffocate with that, too.

This option might be closer to the question's intention, as it uses something that emits a lot less overall energy than a nuclear bomb, but it attacks somewhat fragile tissues.

A pressure suit will hard-counter this weapon. Which could be a Good Thing, actually, as allows a bit of variation.

Anything (that deals damage fast enough)

How their defenses work mechanically is a rather large shield with a constant and pretty strong recharge.

That's why nukes hurt them: An insane amount of damage in a very short timespan. And that's also why they can take tank fire, infantry and the likes (well tank shells might be somewhere near their upper limit): There's almost always that crucial millisecond or two before the next hit, enough for their magic barrier to regenerate.

This would mean that theoretically anything could damage them if enough hits with good enough timing. Realistically only orbital (pulsed) laser platforms, nukes and nuke-like conventional weapons (if even) are an actual option. Maybe those cliché tesla weapons as well since arcs have a moment of insane energy when they start forming.

For balance I would suggest that recharging their barrier takes energy away from other capabilities, meaning that while three platoons of infantry cannot hurt them, they are nearly disabled and only move in slow-motion or so while under constant fire.

My first idea was targeting Required Secondary Powers. Oh? So you're invulnerable? Well then, eat cannonball! My, how far backwards you can fly! Your skin may be unpiercable, but your weight is still pretty average.

From a gameplay perspective, various blasts and projectiles can throw them around; status effects (weak, slow, etc) still affect them; and they can be disarmed. And an invulnerable dude with a sword still isn't going to do much to a tank.

If they get high damage-dealing from their magic too, then you can invent a magic-based countersolution to that (anti-magic field?)

near futuristic weapon that can damage a creature seemingly only start to receive some damage after a nuclear blast.

how about like ionizing laser? I feel like it's that his defense stat is so high only a nuke level attack power starts doing damage, and below that attack it's either like 0 / 1 damage in a sense

if so, something concentrated / have like "piercing defense" attack probably what would damage this creature, my guess is something like laser / a drill like pellets with reinforced shells. basically this creature needs to be handled like how you handle a reinforced tank.

How about Anti-Matter Shells?

A good size projectile of a few pounds fired out of a railgun would be useless. But if it is hollow and inside has an amount of antimatter being held by a magnetic field, things get interesting.

On impact the shell would shatter and the target would be sprayed by antimatter. If your superman is made of regular matter, then the area of impact would annihilate both releasing an awesome amount of radiation and blowing a chunk out of the target.

As others have noted, explosions are not good at delivering energy on a small point, projectiles on the other hand are fairly well suited for that, so unless your hero has a magical shield that has absolutely no issues deflecting kinetic energy I raise you:

For consideration, a 9mm can have (according to Wikipedia) energies in the range of 430 J to 630 J, and (expanded) diameters between 9.1 mm to 18 mm you end up with an energy flux in the order of 106 J/m2. That's with muzzle speeds of around 300 m/s and above and very light projectiles (<10 g).

Contemporary R&D military railguns aim for muzzle speeds of around 3000 m/s and 5 MJ - 50 MJ muzzle energy (again according to Wikipedia). With that we're easily in the ballpark of 108 J/m2 and should be able to exceed it by a fair margin.

And while we're at it: let's see what a tank delivers. I guess I should search for better sources, but yet again according to Wikipedia the M829A3 gets fired with a muzzle energy of 12.1 MJ, and has a penetrator diameter of 25 mm. That yields 2.46 × 1010 J/m2. So a few tanks from close range should also be able to kill your hero.

Your hero is able to deflect the nastiest things thrown at a shield, and barely heat up. But trick you hero into an induction furnace and they are cooked from the inside with a magnetic field that can literally melt steel. An electric arc furnace could work, really big ones are available in the steel industry, and they are usually faster, but that requires an external source that might be blocked by a shield. The induction furnace heats things from the inside as the alternating magnetic field produces massive amounts of heat from eddy currents within the hero's body.