Hey guys, I'm in the process of making a campaign supplement, using the miniatures and terrain from the Rise of the Halflings. I was wanting people's opinions on the big bad; the Great Warlock, and his assistant Digglesby Burrower, the Staff Bearer. Is their combination a little too powerful and are their CR ratings right (in your opinion)?

The Warlock is, in the setting, an authoritarian dictator who became the savior of a province of Halflings by fighting and binding the powerful Celestial Wyrm that was ravaging their township. Now that he is bound to it he has access to its vast knowledge and is using that knowledge to design magical machines fueled by bial harvested from the dragon's fire-making glands. The Staffbearer has been appointed by the Warlock to carry his important items, like his Staff of Power and tomes of knowledge that he has been transcribing.

The party will have met Digglesby Burrower earlier as a representative of the Warlock in the main township, but by the time they meet the Great Warlock himself, the party will be fairly high-leveled, with a good idea of the evils that he has been perpetrating on the halflings of the area, so expect people to want to take him down.

I focused on the halfling's sheet.

1. Should be Challenge, not Challange, in both sheets.
2. The halfling's unarmed strike should be 2 damage, not 1, as his STR mod is +1.
3. The halfling's bonus action not only doesn't do anything at all, 100% of all halflings can do it without spending a bonus action - you can just talk during your turn while you do other things.
4. The syntax for the staff's melee damage is incorrect.  This is what that should look like:
   • The Great Warlock's Staff. Melee Weapon Attack: +4* to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 3 (1d6) fire damage, or 5 (1d8 + 1) bludgeoning damage plus 3 (1d6) fire damage if used with two hands.
   • *:  +4 can't possibly be correct; he has a +1 STR mod which is accurately reflected in his bludgeoning damage (so we know this isn't a +1 staff), and he's CR 2 or CR 3.  He needs to be CR 5 to have a +2 proficiency bonus.  Should be +3 to hit with the staff.
5. You used the wrong hit dice.  A Small creature should use d6 hit dice, d4 is only for Tiny.  Change his hit dice to 4d6+4 and his hit points will remain 18 but use correct hit dice.
6. This halfling is radically below CR 2.  He's CR 1/2 (OCR 1, DCR 0) regardless of whether he has a +3 or +4 to hit in melee.  I used his correct average melee damage of 9 (1d6+1d8+1) to calculate this.  His CR will plummet if the Warlock takes his staff back.

I didn't analyze The Great Warlock beyond verifying he shared the Challange typo, but offhand, his AC and HP seem incredibly low for CR 16. 

Just the two of them on their own won't survive more than a round or two against any party of level 16. It might be a challenge for a party of four of level 10, perhaps. Any party that include a Paladin of level 6 or higher will deal with his spell save DC easily.

I like the concept a lot. A couple things about the Warlock:

• I don't think Digglesby powers him up nearly as you think he might. Spell slots limit PCs because they fight multiple encounters each day, but monsters typically have one encounter and either die or flee for the day. Unless you intend for the battle to last for more than 7 rounds, allowing extra spell slots won't really matter at all.
• With 15 AC and 68 HP, this guy is likely to die in one round against a party of level 5 or higher - maybe even before he gets a turn if they roll well for initiative. A CR 16 typically has 3-5x more HP than this. He should probably have something like Mirror Image up before the fight starts. They're going to tear through Digglesby like a wet paper bag as well.
• He's also got a pretty bad chance of holding concentration with that +0 CON saving throw.

If you want Digglesby to matter, he needs to offer more to the warlock and he needs to not go down the moment he's hit with a stiff breeze. Maybe he can hold the concentration of a spell or something and run away. Maybe he lets you upcast for free.

And I'd bump HP a lot. For both of them, unless they're fighting Digglesby with some minions at level 1. It's ok not to stick hard-and-fast to hit dice/CON calculations, the D&D police are not going to show up at your door.  Pay attention to the amount of damage your party can do in a round and reverse engineer from that. Nothing is more anticlimactic than getting to the BBEG (or any named NPC for that matter) and then steamrolling it with minimal resistance.

If that Warlock is meant to be the end all be all, that dude is going to die a very painful fight.  Power Word Kill just outright kills him, no save.  

You mentioned that hes carrying a Staff of Power, I assume reflavored to be that Great Warlock Staff.  If it is, that thing "While holding it, you gain a +2 bonus to Armor Class, Saving Throws, and spell Attack rolls."  This helps with some survivability, but overall hes still a squishy boy.  +0 to Con saves is some big ouch territory.  

The fear effect being 10 feet is laughable.  The people you want to hit most you won't hit.  

If hes trained in arcana/history, why is he only getting a +1 to both arcana/history, while his charisma skills are getting +4 and his attack is a +6? What's the guys bonus?  Why are we so inconsistent?

Why is the halfings hit die a d4 when a humanoid?  This dude will die to a chromatic orb as no one has counterspells here.

Is this Great Wyrm going to be in the fight as well?