How much health does a detachment have, and do they benefit from Multiple Attackers?

Question

Cairn SRD:

Detachments

Large groups of similar combatants fighting together are treated as a single detachment. When a detachment takes critical damage, it is routed or significantly weakened. When it reaches 0 STR, it is destroyed.

Attacks against detachments by individuals are impaired (excluding blast damage). Attacks against individuals by detachments are enhanced and deal blast damage.

(the text is identical in Cairn 2e playtest.)

I can see two ways of reading this:

1. Detachments are implied to have the equivalent HP of one combatant, because they are "treated as a single", and the singular STR mentioned
2. Detachments have the HP of all combatants combined, because more things should be harder to kill than just one thing

If #1 is the case, then it would seem that this rule also applies:

Multiple Attackers

If multiple attackers target the same foe, roll all damage dice and keep the single highest result.

If a detachment is one "foe", then as a group, you can deal a max of 4 damage per round to the detachment (1d4 because impaired, keep only highest because multiple attackers). This sort of makes sense from a balance perspective, as it makes detachments beefier, but narratively it feels dissonant because you're using a rule about reducing the lethality of many-on-one combat, and applying it in reverse to the detriment of the players because you decided to treat the "many" of your detachment as a "one".

I cairn't figure out which of these readings is intended. Help!

Answer 1

You are correct, it is #1 (the equivalent HP of one combatant) though I'd note that they usually take the "top" HP (a commander of sorts). A dozen soldiers would use their captain's stats, for instance.

You are additionally correct that the multiple attackers rule does apply, and that all attacks would be impaired (e.g. d4 damage from each, keep highest). I actually disagree that there is a difference in this case with respect to "ganging up" vs one-on-one: in combat with a detachment (including a large creature, not just a group) its foes are indeed at a disadvantage: it is larger, more terrifying, etc than they are. Ganging up on a detachment does provide a small bump in power, but likely not enough.

Take for instance the dragon Smaug: does it matter to him whether he is being attacked by six fighters, or just one? They are all as ants to him.

Answer 2

A detachment appears to be a mechanic to facilitate a group of foes fighting together as a unit. The impaired mechanic reflects the multiple foes working together to deflect attacks, and the enhanced and blast mechanics reflect multiple foes working together to amplify damage and attack multiple targets.

I don't see how Multiple Attackers does not apply to the second case, as your post implies. Specifically, it appears to me that the Multiple Attackers mechanic affects both cases, because an Detachment is still a single foe regardless of how its HP is calculated.