AC 16 (scale)
HP 460 (40d12 + 200; bloodied 230)
Speed 50 ft., swim 50 ft.
Proficiency +5; Maneuver DC 22
Saving Throws Str +14, Con +10, Wis +9, Cha +9
Skills Arcana +8, Athletics +14, History +8, Insight +9, Perception +9
Damage Resistances cold
Damage Immunities lightning, thunder
Senses passive Perception 19
Languages Common, Giant
Amphibious. The giant can breathe air and water.
Innate Spellcasting. The giant’s spellcasting ability is Charisma (spell save DC 17). It can innately cast the following spells, requiring no material components:
At will: detect magic , feather fall , levitate , light
3/day each: control water , control weather , water breathing
1/day: commune
Magic Resistance. The giant has advantage on saving throws against spells and magical effects.
ACTIONS
Multiattack. The giant attacks twice with its greatsword.
Greatsword. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 30 (6d6 + 9) slashing damage.
Rock. Ranged Weapon Attack: +12 to hit, range 60/240 ft., one target. Hit: 44 (10d6 + 9) bludgeoning damage. If the target is a Large or smaller creature, it makes a DC 22 Strength saving throw , falling prone on a failure.
Lightning Strike (Recharge 5–6). The giant throws a lightning bolt at a point it can see within 500 feet. Each creature within 10 feet of that point makes a DC 18 Dexterity saving throw , taking 56 (16d6) lightning damage on a success or half the damage on a failure.
Sword Sweep (While Bloodied). The giant makes a greatsword attack against each creature within 10 feet. Each creature hit with this attack makes a DC 22 Strength saving throw , falling prone on a failure.
BONUS ACTIONS
Stomp. Melee Weapon Attack: +14 to hit, reach 5 ft., one Medium or smaller prone target. Hit: 19 (3d6 + 9) bludgeoning damage.
The giant has the following bonus actions, which it can only use while bloodied:
Elite Recovery. The giant ends one negative effect currently affecting it. It can do so as long as it has at least 1 hit point, even while unconscious or incapacitated.
Lightning Sword. The giant moves or swims up to its Speed without provoking opportunity attacks and makes a greatsword attack. On a hit, the target takes 28 (8d6) extra lightning damage.
Lightning Strikes (1/Day). The giant recharges and uses Lightning Strike.
Twister (1/Day). A Large or smaller creature the giant can see within 120 feet makes a DC 18 Strength saving throw . On a failure, it takes 42 (12d6) bludgeoning damage and is caught within a whirlwind or water funnel and restrained for 1 minute. On a success, it takes half damage. A creature can use an action to make a DC 18 Strength saving throw, freeing itself or a creature within its reach from the twister on a success.
Combat
The storm giant attacks with Lightning Strike at every opportunity. It is willing to fight at either close or long range. Storm giants are often too proud to surrender or flee but may offer a ceasefire if close to death.
Names
Agathon, Astrath, Atriveus, Irivis, Mardias, Thelas
Legends and Lore
With a History or Nature check, characters can learn the following:
DC 10 As their name suggests, giants are enormous creatures, the largest of their kind standing over 30 feet tall. Though they look like large humanoids, they are an ancient people with close ties to the elements.
DC 15 Giants sort themselves into different clans, including hill giants, fire giants, cloud giants, and others.
Storm giant royalty receive advanced martial training that makes them the most powerful of all giantkind.
Storm Giant Lone Behavior
1 In a murderous rage after it or its family was wronged
2 Using strange devices to study the stars or ocean depths
3 Promises to help travelers but means to rob and kill them
4 Will allow passage in exchange for information
Storm Giant Group Behavior
1 Raiding creatures who have paid insufficient tribute
2 Ruler and entourage in a palace
3 Summoning a dangerous storm
4 Representatives from different realms meeting to declare war or ceasefire
1 Rapidly gathering storm clouds
2 An immense castle on a distant peak
3 Five-foot-long footprints
4 A distant, immensely loud laugh or shout
Storm giants claim the highest mountain peaks and the deepest ocean trenches as their domain.
CR 11–16 storm giant ; storm giant with blue dragon wyrmling , elephant , ettin , or killer whale
Treasure gold and mithral brooch (2,500 gp), elemental gem (water) , 2 javelins of lightning , necklace of adaptation
CR 17–22 storm giant with cyclops myrmidon , giant water elemental , mammoth , or young silver dragon
Treasure 12 books of prophecy (1,000 gp each), 2 potions of clairvoyance , ewer of storm giant wine (acts as a potion of storm giant strength ), dimensional shackles , gem of seeing
CR 23–30 2 storm giants ; storm giant monarch ; storm giant with 2 cyclopes or water elementals
Treasure giant telescope outfitted with mysterious lenses and counterweights (7,500 gp), gold jewelry box (7,500 gp) containing 5 diamonds (5,000 gp each), set of dice used for fortune telling (they are not weighted but always roll a skull and crossbones) 3 potions of flying , 2 ewers of storm giant wine (each acts as a potion of storm giant strength ), crystal ball , giant slayer (longsword)
CR 31+ storm giant monarch with 1 or 2 storm giants
Treasure 5,000 pp, jeweled gold crown (25,000 gp), mithral belt buckle (7,500 gp), 3 gold rings (2,500 gp each), broken greatsword (if repaired, possibly magical), belt of storm giant strength , hammer of thunderbolts , sovereign glue , universal solvent
Giants look like immense humanoids, standing from 10 feet tall (like ogres ) to 30 (like storm giants ). Some giants, like trolls , have human-like shapes but monstrous features.