Swarms are IMMUNE from Weapon Damage, this is true (Unless you have taken the Vermin Slayer from the Dungeon Delvers Survival Guide) . But a Swung Torch can disperse them, and they are VULNERABLE to ANY AOE Effect (Spells, Flask of oil and the like). They use their SWARM Rating (determined mostly by the size of the swarm) The Large-Sized Swarms we fought in the adventure in Desoto is +10 rating. This was an easy way to make the creature effect cool, usable and not hard to learn. Also it was the best way in my opinion to handle Swarms (be as we do not have hit points and with the Gang up rule being covered in 1,000 rats would mean certain death.
(90 points) Large-Sized Rat Swarm (vermin): Swarm Rating +10 / Speed 6” land (6” Climb) (3” Swim)
Skills: -
Talents: Night Eyes 12”, Natural Climber Talent (Climb Speed same as Land Speed) (10pts base),(Sp)Self Gang-Up Talent (swarm only) (If allowed a Stand & Deliver Combat tactic Swarm Rating is Doubled for attacks and injuries only)(10pts base)
Treasure Rating: Haphazard
Special Attacks and Abilities: Swarm Traits, Self Gang-Up.
With that all said, You are Right and Wrong at the same time. You can't always hurt a creature, but hurting is not the only way to defeat it. you get experience just for facing the thing. So sometimes you need a certain type of attack, Its not IMMUNE TO EVERYTHING! when in doubt RUN or think outside the box. These are all things that we did as old D&d players and we still do them in H/20.
Here is the reason I think you have it a bit wrong: Your an adventurer, it is reasonable to assume you might occasionally get "caught with your pants down" and not have the right tools for the job. It is dangerous to adventure, that is why everyone does not earn thier living by tomb raiding or dragon slaying. There will be times in HACKTASTIC D/20 Fantasy that your PC may not be able to injure a foe. That does not discount what I always say (In our game you always have a chance) Most times a popper(natural 20) or two will get any job done, but sometimes you have to use those neglected things called Skills and Talents to get out of a situation or those even more neglected brain cells, and come up with something. Now I know you are far more Skill and Talent savvy than many or our current players and You are always one to come up with some harebrained scheme to get the job done, so I find it hard to belive that you think everyone doesn't always have a chance.
They have a chance: A chance to buy a freaking torch or even better OIL (you are an adventurer and Dungeons are dark), A Chance to take the vermin slayer template, A Chance to Play a warlock or heck just take an AOE Spell effect, A Chance to RUN or if all elase fails A Chance to wound your buddy and leaving him behind as bait!
I still feel every player has a chance in our game, much more than others. Sure it is deadly, but there are ways around that too. Sure there are some creatures that have IMMUNITIES, hell there are spells and talents that let you have them too. What fun would it be to play if you knew you would always or could always win. You can't always win, but you can always survive, if you are playing by the rules and the GM does not have loaded dice.
In closing I would just like to say, I don't feel it is unreasonable to assume someone might have a torch, a special talent of an AOE effect. If I'm wrong, well now you know to get one of these for your character so to better help your odds when facing swarms. Also now everyone knows they may have to face a MONSTER that may be really nasty and be hard to hurt when they play a Fantasy role-playing game, HUMMM..How Crazy. Who would have imagined? Maybe I should have named it DRAGON HACK, that might have gotten the point across better that HACKTASTIC
Everyone should feel free to comment, they are always read by me and most are welcomed (OK All are welcomed). I try and answer everything that comes my way, so if you have questions I'll try and give you answers. If you have opinions that is cool to, just be ready for me to voice mine. I love our gamers, Grey and I have been friends for years, but we don't always se things the same way. that is what is cool about it. When in deep crap we are sure to come up with different ways out and most usually work, if we can manage to stop picking at each other long enough to try them.
So pay no attention to the man behind the curtain, answers will be given to every Hack Question, heck we might all learn something.