Accurately gauging a boss's strength

[Heliomance]

Okay, my players, you know the drill. This is not for your eyes. This is even more not for your eyes than usual. Stay out.

Spoiler

Show

So, it's not all that long before my players will be fighting the BBEG of the arc. The trouble is, I'm not sure how strong he's going to be, and thus what level I need to get them to. Also, this is my first ever proper boss battle, so advice on running it well would be thoroughly appreciated.

BBEG is either Sorcerer 6/Master of Automata 6 or Artificer 5 or 6/ Master of Automata 6, I haven't decided. One of the main difficulties I'm having is that I have no idea what the Guardian Automata will do to the EL of the encounter.

The party is currently:
Beguiler 6
Werewolf 6, probably hitting Warshaper fairly soon
Gold Dragon Shaman 6
Psychic Rogue 6
Monk 6, picking up the flaming fist/ki blast feats from PHBII
Warblade 5/Martial Bearer of the Ancestral Weapon 1

It's a modern day setting, so technology is available, but I've been quite stingy with the loot so far, they don't have much magic stuff. I was vaguely planning to have the fight once they hit level 8, seeing as there are six of them, but I'm really not sure. Thoughts? Advice?

[Cyrion]

Rather than worrying too much about a numerical calculation of the EL, think about what the characters are able to do against the opponents. How long will it take the PCs to dispose of the automata and/or the BBEG? What resources do the PCs have that will make this easy, or what are they missing that will make it more difficult. What are the first few rounds of action of the BBEG and his minions? How much starch will that take out of the PCs? Answering these kinds of questions will help you balance the encounter.

Also recognize that with 6 PCs they have a very high action potential. If you don't have a goodly number of mooks or several more durable opponents, the party will overwhelm your BBEG on simple action economy.

[Kuma Kode]

In all the battles I've run, the ones where the primary target was a single individual ended up with the party wiping the floor with the enemies. The party will gang up on one target, usually, and take it out fairly quickly, especially if they outnumber it 6 to 1 instead of the usual 4 to 1.

Give the boss speed bump mooks, terrain, defensive abilities, etc. Have the fight be a kind of chase, where the boss seems to be just around the next corner but his automata abound. Have more mooks appear in a second wave partway into the battle so the party suddenly shifts to the defensive. A varied, challenging, and engaging combat is what you want.

Don't even think that a boss behind a wall of mooks is safe. They will range him with bows, eldritch blast, firearms or whatever while the muscle of the group will bull-rush the mooks out of the way.

To answer your question about the automata's EL effects: None.

The automata are a class feature, and are, statistically speaking, an extension of the master. Their presence is accounted for by the +6 CR gain from having 6 levels in Master of Automata, in the same way that any Summon Monster spells are accounted for in the sorcerer's CR. Only mooks or automata you throw in beyond those granted by class abilities count as their own critters.

[Starbuck_II]

Okay, my players, you know the drill. This is not for your eyes. This is even more not for your eyes than usual. Stay out.

Spoiler

Show

So, it's not all that long before my players will be fighting the BBEG of the arc. The trouble is, I'm not sure how strong he's going to be, and thus what level I need to get them to. Also, this is my first ever proper boss battle, so advice on running it well would be thoroughly appreciated.

BBEG is either Sorcerer 6/Master of Automata 6 or Artificer 5 or 6/ Master of Automata 6, I haven't decided. One of the main difficulties I'm having is that I have no idea what the Guardian Automata will do to the EL of the encounter.

The party is currently:
Beguiler 6
Werewolf 6, probably hitting Warshaper fairly soon
Gold Dragon Shaman 6
Psychic Rogue 6
Monk 6, picking up the flaming fist/ki blast feats from PHBII
Warblade 5/Martial Bearer of the Ancestral Weapon 1

It's a modern day setting, so technology is available, but I've been quite stingy with the loot so far, they don't have much magic stuff. I was vaguely planning to have the fight once they hit level 8, seeing as there are six of them, but I'm really not sure. Thoughts? Advice?

Technically, if it is as class feature it doesn't boost EL. So Guardians shouldn't affect it, the balance of the Prc affects EL (one assumes it is a balanced one so 1 for 1 relationship).

Yeah, this is why Druid enemies are tough. You get the Animal Companion for free.

[Heliomance]

I homebrewed the class myself, so I'm not sure about how balanced it is. If people could evaluate that, it would also be appreciated!

[Myth]

Artificer NPCs are boring... Beware of sundering btw.

As always, you can do a mock "end battle" and have a Crafted Contingency or some such save his arse. Lets you gauge if he's too weak or just right. Then amp him up a bit due to preparation.

[rayne_dragon]

The boss doesn't seem too powerful for a group of level 8 adventurers to take on, even with the guardian constructs. I'd second Cyrion's suggestion of thinking what the players are likely to do and trying to plan for it. Also, this is a boss battle, so don't be afraid to make things tough (but winnable) for the players. If it suits the BBEG's personality (and I'm guessing it would) have them focus on making sure they don't get hurt while letting their various minions (I have this great mental image of all the experimental creations they've worked on over the years creeping out of scrap heaps to attack the players) be the main source of damage. Only once the PCs are starting to get injured does the BBEG feel comfortable enough to stand around somewhere where all the PCs can gang up on them.

I also recommend having plenty of minions around for the fight. With 6 PCs you're going to need lots of targets to ditract the players, even if they're just little 1 or 2 HD things. It may also be a good idea to have a few minions that have very powerful attacks to make the players want to take them out even more than the BBEG, who seems like a very obvious target otherwise. Another thing you could do is to find a way to allow waves of minions to join into the battle. That way you can keep sending waves if the fight hasn't been hard enough, or if you feel that the fight has reached the level where the players have been challenged well enough then you can cut off the reinforcements. I personally find it a good way to be able to adjust an encounter on the fly when I'm not sure how tough I need it to be.

[Heliomance]

So, what minions could I give him? He only has two guardian automata available. Advanced Iron Defenders are an obvious option (I've been conveniently ignoring the bit about their destruction hurting the creator, he's already been using Iron Defenders as sentries)

I'm tempted by Raggamoffyns, they seem quite amusing, but they do break the cardinal rule of Thou Shalt Not Remove Control Of A Character From His Player. Also they have no rules on how to make them, not that I'm that bothered by sticking to WBL for him.

[AslanCross]

As always, you can do a mock "end battle" and have a Crafted Contingency or some such save his arse. Lets you gauge if he's too weak or just right. Then amp him up a bit due to preparation.

Or playtest the encounter, using the most common tactics the players use. I've done this before and repeating the test using slightly different parameters (Who wins initiative? Do I give it max HP/HD instead?) often allows me to gauge the boss strength the best.