This post will detail the fire giant pyromancer, your best bet for a nasty fiery death this side of the Elemental Plane of Fire. Believe it or not, I actually had to tone this one down a bit - I originally gave them access to 8th-level spells and incendiary cloud, which I now realize is a particularly horrific spell (since it lasts multiple rounds), which, combined with the Fire in the Blood ability, would have launched the base damage part of the offensive CR all the way up to CR 23! Granted, the rest of the CR calculation would have brought that down, so, if you want a nice CR 14 challenge for your party, just add incendiary cloud to what I'm giving you here, and enjoy the resulting barbecue!
Fire Giant Pyromancer
For fire giants, society, and the ordning, is all based around skill with the forge. While most fire giants use mundane methods to fire up their forges, a select few, those "born with fire in the blood" as a fire giant would put it, are able to heat up their forges through innate magical power. Most often, this fire magic only manifests in minor ways, but it is not uncommon for fire giants with such a gift to further hone their abilities to become efficient and deadly wielders of fire-based magic. These fire giant pyromancers are much more than mundane forge workers - they become potent weapons both offensively and defensively for their communities.
Fire in the Blood
Fire giants are, of course, naturally fiery in nature; however, this usually only manifests in their tolerance of great heat. A few, however, go well beyond this. Gifted by Surtur himself (so fire giants believe) with innate magical powers which give them unprecedented power and control over fire-based magics, these fire giant pyromancers occupy an honored place in fire giant society. As soon as a young fire giant shows the spark (both metaphorically and literally), they are rigorously tested to discover the full extent of their potential power. More experienced pyromancers will harshly (brutally, some might say) push these novices to their limits in order to have them reach their potential as quickly as possible. Periodically, this will result in the magic of some young pyromancers being literally burned out, or, in rare cares, actually killing them, but the end result is a cadre of fire giants sorcerers wielding truly impressive, and terrifying, amounts of fire magic.
Deadly Defenders
Once fully trained, a fire giant pyromancer is truly a frightening force. Should invaders breach the settlement, the local duke will use any pyromancers present as virtual heavy artillery, lobbing fireballs at groups of opponents and creating walls of fire to block their advances. Pyromancers will often team up with fire giant dreadnoughts to form a truly imposing duo - the dreadnoughts block choke points such as doorways with their shields, forming virtually impenetrable barriers, while the more vulnerable pyromancers stand behind and cast their spells over the shoulders of their armored counterparts. From such a safe spot, the pyromancers can center their spells wherever they want - the inhabitants and furnishings of fire giant settlements are virtually fireproof, while most potential invaders, on the other hand, tend not to be. A short time after encountering a fire giant pyromancer, any such intruders are usually reduced to little more than ashes and charred bodies.
Natural Leaders
Besides their ability to produce stupendous amounts of fiery damage, fire giant pyromancers also excel at what is truly important in fire giant society: craftsmanship. Using such spells as heat metal, telekenesis, and disintegrate, they are often able to create items at their forges much more quickly and efficiently than their non-magical counterparts. Moreover, their imposing personalities, combined with their awe-inspiring powers and efficient craftsmanship, make them natural leaders for their communities, often taking on the role of lieutenants for their local dukes. It is not uncommon for fire giant settlements to be ruled by a duke/duchess and a pyromancer as a married couple. Combined with their fire giant dreadnought bodyguards, such a couple make for a formidable duo as heads of state, as well as being nigh-undefeatable foes for anyone foolish enough to challenge them.
Fire Giant Pyromancer
Huge giant (fire giant), lawful evil
Armor Class 10 (13 with mage armor)
Hit Points 187 (15d12 + 90)
Speed 40 ft.
STR 25 (+7) DEX 11 (+0) CON 23 (+6) INT 10 (+0) WIS 14 (+2) CHA 18 (+4)
Saving Throws Dex +4, Con +10, Cha +8
Skills Athletics +11, Perception +6
Damage Immunities fire
Senses passive Perception 16
Languages Giant
Challenge 11 (7,200 XP)
Spellcasting. The giant is a 14th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). It has the following sorcerer spells prepared:
Cantrips (at will): acid splash, fire bolt, light, mage hand, mending, prestidigitation
1st level (4 slots): burning hands, mage armor, magic missile
2nd level (3 slots): heat metal*, scorching ray
3rd level (3 slots): fireball, dispel magic
4th level (3 slots): confusion, wall of fire
5th level (2 slots): cloudkill, telekenesis
6th level (1 slot): disintegrate
7th level (1 slot): delayed blast fireball
*while normally not on the sorcerer spell list, this spell can be learned by fire giant pyromancers.
Fire in the Blood. Any fire damage caused by a spell cast by the giant gains an extra 1 point of damage per die.
Hightened Spell (3/Day). When the giant casts a spell that forces a creature to make a saving throw to resist its effects, it can give one target of the spell disadvantage on its first saving throw made against the spell.
Actions
Iron Quarterstaff. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 17 (3d6 + 7) bludgeoning damage or 20 (3d8 + 7) bludgeoning damage if used two-handed.
Rock. Ranged Weapon Attack: +11 to hit, range 60/240 ft., one target. Hit: 29 (4d10 + 7) bludgeoning damage
Next up, the imposing rulers of fire giant settlements: the fire giant dukes...