One of the reasons I opted to use Mutants and Masterminds 3e for my Mass Effect conversion is that it offers a very flexible set of tools that allow for a number of approaches to GMing, and particularly to building NPCs.
Approach 1: The Detailed (“Official”) method
M&M handles NPCs pretty much the same way it handles PCs, with a couple of differences: 1) NPCs can be whatever PL you want, and 2) they aren’t required to abide by the “15 power points per PL” rule that PCs have. So basically they have whatever traits you need them to have for the story. If you have a program like Hero Lab (which I do and cannot recommend highly enough), it’s a simple matter to build the NPC you need and export it as a neat statblock. Use it as many times as you need it.
Because this method is the most time consuming method, however, I recommend it solely for “named NPCs” who are intended to appear in multiple sessions.
Approach 2: The “Lazy GM” method
This approach, by the way, works equally well for any application of the M&M game engine, whether you’re working with sci-fi, post apocalyptic, super-heroic, or low PL dungeon crawls. By way of giving credit where credit is due, my approach is due largely to the influence of Greywulf and his series on the lazy gm. Read it!
1) Establish PL. Rate offense and defense separately because they may be different. IE Offensive 7, Defensive 6. For minions especially it makes sense to have defensive PL a bit lower; tougher foes might be equal or have better defenses. This obviously varies, though, depending on what sort of fight you’re looking for.
Actually balancing an encounter in M&M is more art than science, and shouldn’t worry you too much. When you get to that point, just provide what makes sense for the story, and if you think it’ll be especially tough than just make sure your players have a chance to earn the Hero Points they’ll need to take it on.
1a) Note the key concept of the NPC – race, basic role, profession, whatever. This is just meant for fluff and provides a guideline that you can refer to later. Let’s say, “Blue Suns Mercenary.” Really, this step should be first, but as long as it happens at some point you’ll be fine.
2) Establish trade offs the same way that PCs do. Say you want to give the above NPC an assault rifle or a sniper rifle. That gives you ranged offense: Damage 5, which leaves 9 for accuracy (total: 14, twice PL). We also want the NPC to be heavily armored and not terribly agile. Let’s make it defenses: Toughness 8, Dodge 4, Parry 3. Will and Fortitude trade off as well. If the enemy is synthetic, just make them immune to Fortitude and cap Will at the defensive PL.
Technically, at this point it’s entirely possible to start using the NPC immediately and flesh out the next few details only when they actually become important to the game.
3) Pick out an effect or two. Any special movement modes? What is that attack? Add Multiattack if it’s an automatic weapon (e.g., the aforementioned assault rifle). Area attacks are capped at PL. How does it defend itself? Armor, shields, a combination of the two? Dodging? Species suggest powers too (Asari attractiveness and (potentially) biotic power, Turian radiation immunity and claws, Krogan or Vorcha regeneration), but only if it becomes important. Until then, leave it blank.
4) Grant Advantages if appropriate when it makes tactical sense to use them. Don’t bother fleshing out the sheet too much more than this.
5) Only flesh out the NPC in detail if they survive the fights and become important to the story. Don’t bother listing Abilities unless they’re needed later. Note skills that are covered by their Aspect. Give a total bonus to these checks equal to 5 if it’s directly related to their role. Most of the time minions take 10 outside of combat. Give a bonus of 8 if it’s a non-minion and their aspect covers it. Otherwise rate it a 0.
The idea is that when you’re done, the resulting NPC has all the information you need to run a fight using them with less than half of the work. Put it on a 3×5 card or a page with notes and use it for as many fights as you want. I’ve done NPCs this way for at least one game (a manga style martial arts game), and been ready to start the fight after writing down about 3 lines of text (concept, then a short line each for the tradeoffs ). I just added more notes as the fight went on and invented more details on the fly. It worked perfectly well, and the players didn’t even notice.
Approach 3: The REALLY Lazy GM method
This approach has 3 simple steps.
1) Find something in the back of the book that looks like it functions sort of like what you need for your next fight – like, say, for Mercenaries you could use the Soldier, SWAT officer, or Militant (or, alternatively, buried in the Roll Call forum on Atomic Think Tank).
2) Steal it. It is, after all, the Stuffer Shack way.
3) Add a trait or two to make it match the idea in your head closer, and refluff to taste. Modify them later if they survive.
Any of the above methods will work, and can be used interchangeably depending on your current needs.