How can I describe combat where player characters face multiple opponents? For example, in 7th Sea there are up to six brutes in a squad. I'd like to have some inspiration for how to describe the actions of the brute squad. Do you describe every attack or do you describe their action in one sentence?
If I correctly understand the question being asked, you are asking us for effective techniquest to use in describing combat against multiple oponents.
I could answer this in an system-agnostic manner, as Im not very familiar with 7th sea, but Im sure you will be able to relate my advice to this system.
What is important for mass combat, I dont think you should elaborate on every single swing that is being made in the fight. It will make an unnatural, chronicle-like feeling, It will feel like a chore. Also, it will slow down the pace of combat - and combat should be dynamic, fast, interesting and involving.
In order to achieve the necessary swiftness, try emphasising the manouvers of the enemy. They could be doing various things, they could try to circle around the hero, get him from the flank, attack from a few directions at once. One opponent could feign an attack just to leap back at the last moment, letting his comrade hit you from an unexpected angle.
The players character cant reliably control what all their opponents are doing all the time, so you dont have to describe it so either. The PC could feel a slash on her forearm and not know from where it came!~
A few fast examples:
"two of them tried circling around you, to get you from the flanks, while the third charged in a crazed bullrush, hacking with his sabre!"
"I roll over my back, in flight cutting the leg of the left one"
[a minor hit]
"The middle ruffian hacked the air where you were just a second ago, so did the one on the right, as you tumbled through your back. The last one was quicker and managed to change the path of his weapon. He managed to cut your arm while you put your sword up his rib cache till it poked out of his back!"
or even shorter:
[enemy team attacks]
"The one on the left leapt towards you, slashing, you see a flash of the blade on the right and somewhere above your arm!"
"I move around the charging one and leap behind him, parrying the blows!"
[rolls high enough to reduce but not eliminate damage]
"You managed to do so, you took a glimpse of the charging one stubling when you felt a stab of pain in your right arm! Another flash barely missed your cheekbone!"
Those could be a lot better. Before setting up such a fight in your campaign, you could think of some typical moves or tactics the players oponnents typically use. You could trywriting a lot of good, dynamic descriptions of such attacks. Later, when you will have to improvise during actual play, youll head will have those good techniques "imprinted" somewhere.
If I am to do the GM job for a swordsmanship-heavy setting, and I think there's gonna be a lot of fighting, I like to read a fight or two from some of my favorite fantasy writers. It inspires me and sometimes makes idea pop out themselves during fights. I particularly like fighting scenes in R.A. Salvatores's and A.Sapkowski's books (the last is best read in Polish, but English was quite good too).
Actually, all that has been said on writing good fighting scenes applies here as well! You could try searching Writers.SE for such questions. Also, I have found a great interview with R.A. Salvatore on fighting scenes:
A few excerpts, just in case the link goes dead:
Mostly, a good fight scene has to start with characters the reader cares about; without a sense of danger, what's the point? Other than that, writing a fight scene is about mechanics (it's got to make sense to people who know something about fighting--kind of like the science in a science fiction book has to pass the physicist test!); about emotion (anyone who's ever been in a fight, sporting or for real, knows that you go to a different place in such a situation); and mostly, a good fight scene is about the pacing. I notice that my sentences get shorter, paragraphs become single sentences or even sentence fragments, and characters are too involved in staying alive to muse about the meaning of life.
What makes this fight stand out the most for me is the diversity; it takes place in, around, and on top of an inn called The Dragon's Codpiece--that should tell you something, right there.. I've got a pair of crazy dwarves engaging in something part barroom brawl and part vaudeville slapstick in one place, ending with one dwarf holding a guy by the ankles and spinning him around, while the dwarf's brother tries to properly line up a chop of his great-axe to split the fool in half as he swings by. Meanwhile, one of my protagonists faces her greatest fear and greatest enemy in a deadly serious contest on the roof of the building. There are so many moving parts.
The question is very broad and quite subjective, but I hope I helped!