Overwhelm Rules

Into the Odd featured these Detachment rules that I ended up really liking. They're more character-focused then mass combat; but are instantly useful if you want to say how a character can (or more accurately, cannot) fight a massive group of soldiers.

To summarize; Detachments were groups of 50+ men or more that dealt enhanced damage to characters and couldn't be fought except with something that could actually damage a large group of men in any efficient amount of time. You could kill individuals but that wouldn't be enough to stop the main mass of the group from destroying you with sheer numbers and overwhelming force. Sooga games promised us extra rules for this; but never delivered. That bastard. Here's mine.

Overwhelm

When you are facing a force far beyond something a small rag-tag team of adventurers could reasonably fight in combat; you are being Overwhelmed. There are three types.

Numbers

An army or detachment of men of at least 50+ members is considered a detachment. Regular character attacks do not harm the detachment unless the attack is explosive or large scale. Spells that do not target multiple enemies are not effective against detachments. Detachments deal 1d12 damage to each enemy they are facing per turn; no to hit roll needed. If you consider this too powerful, instead let the Detachment make one attack with advantage per round against each enemy; using the highest to-hit modifier any of its member have.

Huge

Huge enemies include something very large; something bigger then your average big adult dragon would have to count. Massive tarrasques or boar-headedworms from beneath the earth might count. In the same way, attacks can only hurt Huge enemies if the weapon itself is huge, at least as proportionally large as a knife would be to a human or magical enough to count as huge. Area of effect spells or body-affecting spells are not effective against huge monsters. Any attacks the boss makes deals 1d12 damage again from simple stomps and great sweeping tail slams.

Superior/Divine

For demigods, avatars of gods, or spirit beings of power levels far beyond normal mortals a divine being is considered enhanced in the same was a Detachment or Huge monster is; despite being an individual. You can't hurt a divine being unless you have a supremely magic weapon, or something of sufficiently opposed energy in order to actually harm the immortal- any attack or spell you cast would brush off them without harm or be easily deflected. Divine beings deal 1d12 damage against everyone; a simple wave of their sword cuts any foe even without physical contact in a wave extending outwards from the attack; they are far above you.

If your character is at 10^th level, they may be capable of facing something enhanced via Overwhelmed rules head on of ONE template. So a level 10 Fighter could fight an enemy detachment as though it was stated as a single unit, or may actually be able to injure a giant creature, or may be able to duel a demigod without immediately being defeated. Two different types of Overwhelmed types or equivalents could also face each other without issue; an army could fight a huge beast somewhat effectively from sheer numbers and so on.

Multiple stacking rules; such as a huge godling or an army of giant monsters, count as being enhanced twice as much. Their attacks count as save or die effects instead of 1d12 against anything that isn't at least level 10 or also a detachment-tier powerhouse; plus they are essentially invulnerable unless the foe they are facing is also at detachment level or "stronger". Players don't really get to this level without some serious bullshit.