Here are the stats and updated flavor text for the revised Fire Giant Duke and the stats for Cloud Giant Count (the revisions for the count are very minor, mainly adjusting the INT and the various things associated with it, but even that minor adjustment raised its CR).
Fire Giant Duke (revised)
Of all the types of giants, fire giants are the most regimented. Their society consists of a strict hierarchy, with each giant fulfilling a certain role based on his or her place in the ordning. Each individual's status is dependent on its skill at the forge - those who can do little more than shovel fuel and run the bellows are among the lowest levels of society, while the more talented artisans rank above, with their standing based on the skill of their craftsmanship. At the pinnacle of this society are the dukes and duchesses, whose skill at the forge is so beyond reproach that Sutur himself has seemingly blessed them with souls of flame.
Family Traditions
For the most part, the political system for each type of giant is some form of meritocracy, based on each race's view of the ordning - whoever is best at doing what each race thinks is ideal self-evidently should be the leader and, as a result, is virtually always considered to be so. From an outside perspective, fire giants seem to be the exception to this rule, since at first glance they seem to have something near a hereditary form of succession. Upon closer examination, however, this seeming paradox can be easily explained - fire giants base their status on craftsmanship at the forge, which is something that can be taught and securely passed down from one generation to the next, unlike, say, gluttony for hill giants or prowess in battle for frost giants. Upper-caste fire giants "game" the ordning, so to speak, by keeping certain crafting secrets within the family. As a result, families that have a large collection of such secrets gain significant advantage when it comes to being ranked in fire giant society. A typical fire giant duke or duchess will have a great amount of such proprietary knowledge, and will usually pass these secrets on to the most promising member of their family, so that the succession to the throne is secured from generation to generation. The downside to this is that the early death of a fire giant duke before such information can be transmitted to the designated heir will often mean the downfall of the dynasty, usually resulting in a short succession crisis until the new duke can be determined and raised. Sometimes this period passes relatively peacefully, with a simple contest of craftsmanship to determine the next duke. Sometimes, however, more violent means, ranging from murders and "accidents" to cull the field of potential candidates a bit, to outright civil war, are certainly not unheard of.
Blessed by Surtur
Showing skill at the forge pleases Surtur, and none please him more than the fire giant dukes and duchesses. Their very weapons (usually great mauls in imitation of the hammers they wield at the forge) are infused with his fiery power, such that, when they smash into the armor of their foes, great bursts of flame often flash out, incinerating any who are not immune or protected from the blazing heat. Those foolish enough to face a duke or duchess directly in melee combat (a rare occurrence, given their usual bodyguard of dreadnoughts and pyromancers) usually find themselves quickly smashed into a bloody, smoldering pulp.
Fire Giant Duke (Revised)
Huge giant (fire giant), lawful evil
Armor Class 18 (plate)
Hit Points 216 (16d12 + 112)
Speed 30 ft.
STR 27 (+8) DEX 12 (+1) CON 25 (+7) INT 13 (+1) WIS 14 (+2) CHA 13 (+1)
Saving Throws Dex +6, Con +12, Cha +6
Skills Athletics +13, Perception +7
Damage Immunities fire
Senses passive Perception 17
Languages Giant
Challenge 14 (11,500 XP)
Second Wind (Recharges after a Short or Long Rest). The giant has a limited well of stamina that it can draw on to protect itself from harm. On the giant's turn, it can use a bonus action to regain 11 (1d10 + 16) hit points.
Indomitable (Recharges after a Long Rest). The giant can reroll a saving throw that it fails. If the giant does so, it must use the new roll.
Improved Critical. The giant's weapon attacks score a critical hit on a roll of 19 or 20.
Actions
Multiattack. The giant makes two maul attacks.
Maul. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 29 (6d6 + 8) bludgeoning damage plus 3 (1d6) fire damage.
Rock. Ranged Weapon Attack: +13 to hit, range 60/240 ft., one target. Hit: 30 (4d10 + 8) bludgeoning damage plus 3 (1d6) fire damage.
Immolating Blow (Recharge 5-6). The giant focuses its strength and its fiery nature on a single mighty blow. When the giant successfully hits a target, as a bonus action it can cause raw fiery power to burst forth from its weapon as the blow lands. All creatures within 10 feet of the target, including the target itself, must make a DC 21 Dexterity save or take 35 (10d6) points of fire damage on a failed save, or half as much damage on a successful one. Any creature failing its saving throw is set alight from the flames. Until a creature takes an action to douse the fire, the target takes 10 (3d6) fire damage at the start of each of its turns.
Cloud Giant Count (Revised)
(Flavor text is the same, so refer to the earlier post)
Cloud Giant Count (Revised)
Huge giant (cloud giant), neutral good (50%) or neutral evil (50%)
Armor Class 14 (natural armor)
Hit Points 275 (22d12 + 130)
Speed 40 ft.
STR 27 (+8) DEX 10 (+0) CON 22 (+6) INT 20 (+5) WIS 16 (+3) CHA 16 (+3)
Saving Throws Con +10, Wis +8, Cha +8
Skills Insight +9, Perception +8
Senses passive Perception 18
Languages Common, Giant
Challenge 16 (15,000 XP)
Keen Smell The Giant has advantage on Wisdom (Perception) checks that rely on smell.
Innate Spellcasting The giant's innate spellcasting ability is Charisma. It can innately cast the following spells, requiring no material components:
At will: detect magic, fog cloud, light
3/day each: feather fall, fly, misty step, telekinesis
1/day each: control weather, gaseous form
Spellcasting. The giant is a 15h-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 18, +10 to hit with spell attacks). The giant has the following wizard spells prepared:
Cantrips (at will): chill touch, mage hand, mending, prestidigitation, ray of frost*
1st level (4 slots): magic missile*, shield, thunderwave*, unseen servant
2nd level (3 slots): gust of wind*, mirror image, web
3rd level (3 slots): dispel magic, sleet storm, stinking cloud
4th level (3 slots): confusion, fire shield, ice storm*
5th level (2 slots): cloudkill, cone of cold*
6th level (1 slot): Otiluke's freezing sphere*, wall of ice*
7th level (1 slot): reverse gravity
8th level (1 slot): power word stun
*Evocation spell
Empowered Evocation. The giant adds its Intelligence modifier (+5) to the damage roll of any evocation spell it casts.
Sculpt Spells. When the giant casts an evocation spell that targets other creatures it can see, it can choose a number of them equal to 1 + the spell's level. These creatures automatically succeed on their saving throws against the spell. If a successful save means a chosen creature would take half damage from the spell, it instead takes no damage from it.
Improved Fog Cloud (3/Day). As a bonus action, the giant can call into being an advanced fog cloud. This functions as the spell of the same name, except it is transparent to cloud giants, and any creature that is not a cloud giant that enters the cloud or ends its turn within the cloud takes 7 (2d6) cold damage.
Actions
Multiattack. The giant makes two morningstar attacks.
Morningstar. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 8) piercing damage.
Rock. Ranged Weapon Attack: +13 to hit, range 60/240 ft., one target. Hit: 30 (4d10 + 8) bludgeoning damage.
I'll post the rest once they are completed! Also, please feel free to comment on the fire giant revision. Is the improved critical too much? Perhaps Indomitable should be 3X day?