My first advice would be not using a single, solitaire Big Bad Evil Guy. Give this Alchemist some help from henchmen and mooks. They don't need to be too competent, or dangerous. They need to be there, and occupy space, and soak some hits, and do some damage, or throw some conditions to the party.
If an encounter consists in a single BBEG, it's easier to screw up. It's easier to have him lose initiative, then die before he can even act, and if you beef him so the PC can't kill him so easy, you risk going the other way and kill the party. If you mix some henchmen, you balance the action economy, and you can also buff the total hit points from the bad guys (which basically measure the amount of time the PC need to cut through it), without really increasing other values from the alchemist. You should provide us with a few more data, like the levels. But let's say you have an alchemist with 50 hp. By adding 4 henchmen with 15hp each, you have more than doubled the total "hit point sponge" the PC need to deplete in order to win. You could do that with an alchemist that has double the HP, but to do so, he'll need to be higher level, which also means he'll have access to higher level spells (extracts, in this case), and bombs, and other class abilities. The 4 extra henchmen would probably be less dangerous, but allow you to move them around, flank, do some damage, maybe cast a low level spell or use a potion, etc.
Another suggestion I can do, is focus your BBEG ability in surviving. If you focus him too much on damage, two things happen: you can kill your party, and your party will start a damage race to try to kill before dying. Both things will make for a short encounter. In my experience, best BBEG are those who focus on "control", because they present challenges that the party has to overcome. For example, if your alchemist spend a turn drinking a Spider Climb potion, and then climbs the walls, and reachs a balcony, he presents the party a new challenge (How do we get there?).
A group of 3-5 lvl 2 will not have a lot of resources. I remember a fight I did, against a group of level 2, which had a goblin alchemist. The goblin alchemist had 2 dogs in 2 separated cages, which he planed to experiment with, if he ever overcame the fear. There was a group of goblins (I can't remember, but I think that they were 4) henchmen with him. In the floor, there were some trapdoors, with zombies. When someone steps on one of those trapdoors, the zombies try to grab them, inmobilizing them.
he goblins were trying to open the trapdoors, working in pairs, to free the zombies, and used reach weapons to redirect the zombies toward the PC. If the PC manage to disarm or kill the goblin with the reach weapon, the zombies will be just as likely to turn against the goblins, than to attack the PC. Meanwhile, the Goblin Alchemist is behind those goblins, far away, safely chugging some potions and extracts to buff himself.
This present the PC several challenges: They have to avoid the trapdoors, or they risk to be trapped. They want to deal with the alchemist soon, before he buffs himself too much, but they can't ignore the other goblins working in pairs, because they can open trapdoors, freeing zombies, and making the encounter more dangerous. But they also have a possibility to enhance their chances, if they free the cages somehow (a mage hand spell, moving with acrobatics over the trapdoors and the goblin henchmen, etc). If they do so, they'll gain dog allies. If they can kill the goblins, and use the reach weapons themselves, they can try to redirect the zombies against the alchemmist as well.
Hope this helps to inspire you with your own ideas.
First thing you need is your PCs. Then check their own AC and their own attack, and his hit points. That way you can see how hard it is for them to hit this alchemist. If your party has +5 or +6 to hit, and you give your alchemist AC 23, and they only hit with a 18, they'll be in real trouble.
The goblin alchemist in the encounter I mention above had 27hp and AC 16. Was extremely strong for a goblin (once buffed with the mutagen and Enlarge potion) and had +6 attack and 2d6+6 damage, but keep in mind that he spent a few turns in the background, self-buffing, with the party having to worry about the rest of the goblins, the trapdoors, and any zombies that could get free. He still was very dangerous for a lvl 2 character once he joined the fray.
I'd use the cartographer as one of the BBEG's henchmen.
Ive planned the adventure to go as such
-Players meet by some means in the city by means which ill figure out once I get in all their back stories
-Players are in some way hired or forced into accompanying a cartographer to chart a mysterious island a few miles out of town. I also thought that maybe the wealthy family that hired them paid them in advance in order to help bolster up the group a bit more. There would be some legends or tales of the dangers but very little recorded info about the island
If you're worried about your players being dicks by having their PCs not going along with the adventure, talk to them. RPGs are cooperative games, everyone should know that. If forcing a PC seems like a good idea story-wise, talk to the player beforehand. Playing reluctant characters that still cooperate with the GM and the party is often interesting, but it's hard and you need to be open with what you're doing so others don't think you're a dick.
-Upon arrival, the PCs somehow fall into an inescapable gas trap to which they all fall unconscious and find themselves locked within a cell. At this point, I haven't quite made a decision if id want the PCs to briefly meet the BBEG at the cells or if they should come across him and meet him for the first time deep in his laboratory. If they don't initially meet him, I wanted to have him taunt them through some kind of magical means. An seeming disembodied voice as they progress closer and closer to his lair.
Players absolutely hate having their PCs captured in this fashion. Takes away player agency. Rethink this section of the adventure.
If you really need to trap the PCs, remove the gas trap and settle for a simple door closing behind them. But even then, it reeks of shoddy GMing. Adventures should be ineresting enough that the players want to follow them.
Id like the characters to have more of a reason to kill this BBEG other than just "He is a bad dude" I wanted to come up with a situation where they are more emotionally tied to the character. Maybe he killed there cartographer friend or experimented on him. Maybe he can even appear as a brainless enemy with weird mutated features. This would give off the impression that the same could happen to them if they don't end the BBEG.
Have the PCs meet the BBEG before the reach his dungeon. In town, perhaps. Just recognizing the guy goes a long way. The PCs should not realize he's the villain in that first encounter, but then be able to gather that he is evil and did some heinous act that time they met him in town.
An easy way to create some feelings in your players is to have the villain's victims be similar to the PCs. The alchemist has deliberately target members of the same race or church as one or several of the PCs, for example.
|
Dont focus in only one encounter, your big bad evil guy may fail a save and die in one turn, also let that happen. People does enjoy when that kind of stuff happen so dont just say: the guy is inmmune.
Remember that hazzards like traps, a big hole or things like that many times tend to be more deadly than a simple boss.
And for the balance, dont be affraid to rebalance the enemies in the middle od the game if you see they arre too weak/strong