What's the class of the PC here? And what exactly is the story between him and this evil dude? What kind of military history does the evil dude have also?
These are things I keep in mind when giving a character's abilities and encounters. From what you said, I think you should definitely give the PC a chance to do a one on one fight kind of. Have everyone else attack the monsters and give him the opportunity to attack the bad dude. This will work especially if the PC and the evil dude's personalities would support them doing this anyways.
Keep in mind that as the dm, you are not restricted to making the bad guys chained to a set class or classes. You can make any monster or character you want, with whatever abilities you want. What I mean is don't worry about the summoner/fighter/magus idea too much. You can if you want give him the abilities of a very strong fighter character that is also able to cast at a very high level of spells. My point is, make his stats and abilities whatever numbers you want them to be regardless of the player rules. As long as the encounter is memorable and fun, that's what counts in the end.
From what you've got described here, I think it would be cool if the enemy was camping on a high tower throwing spells and arrows down at the party. His evil minions attack the party as well and they have to climb their way up to the tower to face him. And when you get there have him do something totally unexpected that will freak the pcs out. Like him turning into a dragon or something. Or have him use the whip style that you liked. If I was making this encounter I think I'd do something like that.
Ok that's a cool backstory. If I was the PC, I would definitely have kept the chains/whip/whatever that atius used to abuse the PC. Then as the PC I'd try to hang atius with it or something. Take him out with his own oppressive tools! If you want you can tell your player this. Or if you want to do this from the dm side, maybe you can have atius do or show something to the PC that is traumatizing to him.
If you want to keep atius' class close to the rules, going by your description I'd do this. Make him a whip using Magus specializing in summoning spells. Now I haven't used a Magus before so I don't know how much summoning they can do. So if they don't have any summoning abilities, you can just have him command the hordes of monsters/demons already at his keep like you said.
Also to make things interesting, you can take advantage over the fact that most of them are martials. But not too much, just enough to scare the crap out of your players. For example you can have atius wrap his whip around a player and hang him over the edge of the keep. And if he fell it would mean death for him. A caster would be fine because they can fly or do feather fall. But in this situation, it can be fun to have atius laugh and hang him there while everyone figures out a way to save him. Whatever it is, be sure to give him a way out to, but not something too obvious.
Cavalier gets bonus Teamwork feats and has people skills.
A Cavalier/Sorcerer/Eldritch Knight would make a good witchking type.
My only issue with your Summoner idea is that the eidolon might over shadow the nemesis....or be the big surprise on top of the tower!
I don't think it really matters if the nemesis's allies are hired or summoned. Just that they're there. So magus or summoner. Magi have lots of "trump card" abilities that can help with escape and surviving, and are pretty much built for magical martial fighting: buffing, debuffing, mobility, sensory, and nova/blasting.
Is the bad guy an orc or half-orc? A scarred witchdoctor witch might work. He would even have an evil magical mask to hide the scars left behind by the boiling water. And Con as a primary casting stat means he would be tough. And Hexes are fun.
Free yourself from the "class" concept when you build NPC's, especially bosses.
Classes are made for players to make characters who are balanced among themselves. As GM you should use the GM tools to make an enemy encounter, using the tables and statistics in the bestiary as a guideline, especially table 1-1 on page 291, that table is your golden rule chart. Classing and multiclassing is an overly complex method to get something that may wind up being very badly balanced.
Example: A Level 4 fighter NPC can easily be wearing Full plate armor, with a Heavy shield and have a dex bonus of 1, his AC would be 22 not counting feats, but the recommended AC of a cr 3 opponent is 15.
You might want to give a Boss lots of extra HP though, save bonuses and some Hero points.
Once you know the numbers to aim for, cherry pick the abilities you want.
For the summoner idea:
You need a high BAB for those arrows to hit anything. Make sure his BAB is at least equal to the party ECL and youll be set there.
To summon monsters just give him the unique ability to cast Summon monster (of appropriate level for the party ECL). It would be apt to make it usable 4 times per day, between the archery, mount control and bragging he will only get so many spells off, a couple of Hero points would really help him pop down some critters.
The mount should be a completely seperate creature with its own profile, you can give the creature and the boss some custom feats for free to represent the bond, something as simple as "While adjacent the boss gets +4 AC & +2 saves", make sure he has a variation of "Makers call", because thats such a thematic Summoner ability. Once he uses that the players cant help but think theire up against an authentic summoner.
Once youve got all that then the level appropriate amoutn of feats should take care of making him a proper archer.
Summary:
BAB equal to the players level.
Summon monster XZY 4 / day + some hero points.
Custom/Reskinned monster which grants the Boss a defensive bonus and serves as a mount, 1/battle the boss can use makers call on it.
Those are the only things you need to make this fight like an authentic fight vs a powerful summoner / archer.
For the Whip Warlord idea:
You can reskin the whip however you want (Replace the leather with Barbed chain links = Lethal damage, if somebody cries "Whips dont work like that" just tell them "MAGIC!").
A Bunch of fighter levels, in this case it is appropriate and simple way to give him the feats he needs to keep up a Shield + Whip combat style, make sure to DM fiat his HP into the Stratosphere.
You can give him an aura to represent the warlord effect, Allies within 30ft get +2 Attack and AC, Allies within 10ft get +4 Attack and AC, Allies within 5ft get +6 Attack and AC. The aura would work in reverse for him, granting him a +1 bonus to Attack & AC for every ally within 10ft.
Finally a couple of Hero points reserved for movement and Tripping/Disarming/Bull rushing would help make the fight more thematic.
Summary:
Lethal damage whip.
Lots of feats to dump on his shield and Whip and a "PLOT" amount of HP.
Buffing aura that benefits both him and his minions.
Hero points to fuel combat maneuvers.
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Of course you can allways combine the two suggestions ;)
Also, even if you dont like my other ideas, the whole "evil heart" and 1 v 1 thing has an additional level of possibility.
You might try splitting this bossfight into 2 fights, where the boss has 2 different statlines.
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Step 1.
Establish a ticking clock. Perhaps the boss has just opened a portal in his fortress and is waiting for a big demon to come through.
Step 2.
The first boss fight is the flying summoner fight, where he revels in his Evil powers and corrupt magics, where the entire party is fighting to bring him, his minions and his monster down. If the boss goes down first have him disappear mid fight after a feigned death, if hes the last to go down have him use a Hero point to Teleport away dramatically, hes a summoner so Teleport is a perfectly legal escape method. The players will want to heal up quickly before delving deeper.
Step 3.
The second boss fight would happen inside, in a big command room with plenty of closed doors on either side of where the players enter.
At first there's just some big brute in the room (Good ac, medium attack bonus, higher then average damage), it feels like an ambush but if I understand the player you described proper then hes likely to charge anyway.
Once the player is committed and his teammates hang back the trap is sprung, fill the room with chaff creatures, low CR warriors, the melee guy(s) will now be cut off from their buddys, it will all look rather desperate, in the meantime the big brute in the middle ough to activate a lot of defense abilities, Combat expertise and Power attack, if he hits hell draw lots of attention and keep the reccless guy committed while everyone else tries to regroup.
Then while this fight is at its high point, enter suited up Boss with a melee focused Whip and shield combat style bellowing duel challenges.
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I hope my ideas gave you some inspiration.
Nice ideas and it sounds like a fun game. Kudos. You seem to have a fertile imagination. I am sure the specifics will fall into place. Here are my general points for "nemesis" NPCs:
1. Former connection with PC(s).
2. Morally ambiguous but identifiable agenda (e.g., killing the maiden daughters of the town guard because wife was slain on wedding night by same)
3. Does/says/believes things the players would hate (as well as their PCs). (to elicit emotional involvement from players)
4. Escapes to fight another day (once or twice ONLY) OR is survived by a relative or flunky who the PCs know will seek vengeance at a later date.
5. A memorable schtick - appearance, laugh, voice, catch phrase, calling cards, signature gear, etc.
Maybe Galanost Laetalal from my Character Gallery will serve your purposes? He is a great warrior who was horrifically scarred. He would make for quite a powerful nemesis.
Epic boss battles are incredibly fun when they execute properly and incredibly frustrating for everyone (especially the GM) when they don’t go off as intended.
You seem to have a good idea on what you want the BBEG to be (so I've skipped that advice) and have already hit several of the main things I always like to see in epic boss battles – player investment (the PC has a motivation to go after this NPC), recurring villain and thematic backstory.
Assuming the BBEG is anticipating a visit from the party (especially the one who left him maimed), I would try to set things up with a nice environment to keep the battle challenging for the PCs and let everyone feel like they have something to do other than surround & pound the BBEG.
Since he was already burned by the PC – I would probably make him either nigh invulnerable due to being paranoid about it happening again & worse or make it fatal flaw type of thing where PCs can debuff or otherwise manipulate him using his fear of burning / scalding against him.
This seems like it would be a good place to have an action movie style scene with catwalks, giant cauldrons of boiling liquids and clouds of steam or noxious vapors cutting down on visibility – the BBEG could be an excellent mobile opponent trying to draw PCs into pre-planned ambushes or mechanical traps and using the lack of visibility against the PCs – especially if he has some way of seeing through it (ala waves oracle/ninja builds or wearing a goz mask).
Whatever you do though, don’t forget the minions – almost no fight is going to go well with just one bad guy – action economy is definitely something to consider. I’d recommend you have a few minions to slow the party, but even more guarding or preparing to kill prisoners or hostages that the PCs may be invested in protecting. This lets the PC with the most emotional investment in the BBEG focus on them and still gives the other PCs something to do in the fight and feel like they are contributing.
Using the example above, the BBEG may have taken several prisoners for specific purposes and some of his minions may be compelled rather than volunteers, giving the PCs the option to find a way to try to weaken the BBEG before going in for the kill. Perhaps he has the children of a few life oracles with orders that they be killed if anything happens to him, with the end result of him having incredible healing for at least the first few rounds of combat (via multiple life links) if the PCs don’t find a way to neutralize it. While the PC with the backstory investment keeps the BBEG busy, the others can find and release the prisoners which causes the compelled allies to revolt against the BBEG (and maybe switch sides and buff the PCs instead).
For minions, the BBEG has a combination of animated objects placed in strategic areas (to try to bull rush PCs off of the catwalks, or who are perhaps part of the environment such as animated ladders), as well as at least one “LT” minion, several tough bodyguard minions and at least one “buff/escape” minion whose job is to make sure that the BBEG can (at least temporarily) escape (such as using the Shadow Well ability of the Shadow Sorcerer Bloodline).
… and last, but not least, make sure the BBEG is at least a little bit smart and has contingency plans for common PC tactics (such as blindness, disarm/sunder, etc. I would have a set of code words he and his minions yell back and forth to each other throughout the combat and especially a sequence of “all is fine, no need to activate a contingency plan yet” words that don’t work if used out of order (as opponents would likely start yelling them back if they think it will help the situation). Extra points if they are in a specific & obscure language that one of the other PCs may unexpectedly know.
Hope that helps.
-TimD
You'll have to tell us how it goes when the big show down goes down!
Yes, please do, I love hearing how boss fights panned out! :)
My first thought is a crusader archetyped cleric of a madness, pain, or sadist deity. When the pain of the events you detailed came upon him the nemesis snapped and now he likes pain or transformed him into what he is now. DC Comics the Joker is a decent comparison of the idea. A cleric has advantage of being able to fight anyway you want him to. Waves of undead, summoned creatures, martial prowess, save or sucks to torture PC, etc etc all in one class.
Extended Heightened murderous command!!!!!!