New GM here and I'm not quite sure how CL is calculated. So, the CL of an encounter (involving multiple enemies) is suppose to be the combined CL of all enemies/3. But that doesn't make sense. That means a single CL20 enemy will trounce a party of lv 13s, but 2 CL 20 enemies is a fair fight? Do you divide by 3 if there's only one enemy as well? A party of lv 6s taking on a CL 20 boss just seems a bit...off. I'm just really confused as to how this works.
For groups of enemies consisting of a single enemy type, the books suggests that a number of enemies equal in both quantity and level to the heroes will provide a decent fight.
"...for example, a 1st-level hero should find a CL 1 stormtrooper challenging. By extension, four CL 1 stormtroopers should prove challenging to four 1st-level heroes."~Saga Edition Core Rulebook p. 247
The (Total CL)/3 rule only applies when you encounter one of the following situations:
- The number of enemies does not equal the number of heroes in the group
- The enemies consist of different types and/or CLs
To calculate the CL in these situations, you take the sum of all the enemy's CLs, divide it by three, and round down.
This number assumes that you have four party members. Add one to the number for each person less, and subtract one for each person more.
The encounter is considered 'fair' for a party that is within one level of this number.
So, for your examples:
Single CL 20 Enemy
20/3 = 6.66 => 6
A party of four level 5,6, or 7 heroes (or a single level 20 hero) would find this encounter challenging, but survivable.
Two CL 20 Enemies
(20 + 20)/ 3 = 13.33 => 13
A party of four level 12,13, or 14 heroes (or two level 20 heroes) would find this encounter challenging, but survivable.
One should also modify CL based on conditions of the party and enemies. Step an enemy's CL down by one if they're injured or at a disadvantage, or up it by one if they have an advantage.
The 2nd level party finds a group of six CL1 storm troopers. Normally this would result in a CL of 2, but due to the party setting off alarms earlier, the troopers are set up behind some cover. Each of these troopers will have their CL increased by 1 for their advantage, making the calculation:
(2 + 2 + 2 + 2 + 2 + 2)/3 = 4
The challenge level is is no longer considered 'fair', but instead challenging. These modifiers should also impact any XP the group receives.
From what I've played/run of this game, I've found it important to remember that these numbers seem to assume a fresh party. Though it says a party of level 6's could take on a dark jedi, that's only with all their abilities intact. If they've already used their resources, they'll get torn apart.
Hope it makes a little more sense now.
When it comes to figuring out how difficult an encounter is I usually resort back to the somewhat complex way that DnD 3.5 calculated things. You add +2 to the encounter's challenge each time you double the number of individuals at a given CL. Some elite soldier type may be CL 4 but having two should appropriate for a party of 6th-level characters.
If it helps remember than one on one an opponent with a CL = the PCs level should have a 50:50 chance of winning! Consider things appropriately.