Giants have often been attributed to living in complex societies with vast magical knowledge, and histories and legacies of their own demigodly heroes. These great figures are able to pass along runic knowledge and other special magic techniques to empower those who serve these pacts with special skills to help empower them by augmenting their size and their magical skills both. Whether in a pact with Fire Giants, Frost Giants, Storm Giants, Stone Giants, or Hill Giants, these spellcasters often wield unique Giantish runes to cast arcane spells and utilize some additional power with ritual spells. When utilizing their powers, they can utilize these special runes if they have the space to make them larger in the space around them, and cause even more powerful spell effects based on the size of the rune used.

Expanded Spell List

1st-level Giant Pact feature

The Giant patron lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Giant Expanded Spells

Runic Spellcasting

1st-level Giant Pact feature

At 1st level when you choose this Pact, you can add special power to spells you cast and cantrips you use. You gain proficiency in Arcana. Additionally, you have a number of Rune Dice, which are d8's, equal to your Proficiency Bonus. Whenever you finish a short rest, you may regain all expended Rune Dice. When you cast a spell or cantrip, if you can draw a rune in the air in your space, you may expend one of your Rune Dice for one of the following benefits:
Fire Rune: when you deal damage with a spell or cantrip, you may roll and expend a Rune Die, adding that much magical fire damage to the damage you deal with that spell. 
Frost Rune: when you succeed at a spell attack roll or a spell target fails its saving throw, you may cause that target to have its speed reduced by 10 until the beginning of your next turn.
Storm Rune: when you succeed at a spell attack roll or a spell target fails its saving throw, you may cause that target to be pushed 10 feet horizontally in a direction away from you.
Stone Rune: when you cast the spell or cantrip, you may roll the Rune Die and gain temporary hit points equal to the number rolled.
Hill Rune: when you cast the spell or cantrip, if one of the targets is a friendly creature or yourself, roll the Rune Die and restore hit points equal to the number rolled.

The size of your Rune Dice improves to d10's at 14th level.

Giant Runes

6th-level Giant Pact feature

At 6th level, you learn to improve your capacity for your Runic Spells, drawing larger runes for greater spell effects. When you cast a spell or a cantrip, you can use your Runic Spellcasting feature using an additional Rune Die, as long as you are expending both dice for the same rune effect, and as long as you have a 10 foot square space to draw a large size magical rune in the air. You may also expend one additional die for the same effect (or 3 total Rune Dice), as long as you have a 20 foot square space to draw a huge size magical rune in the air. The effects of multiple Rune Dice spent are cumulative, and dice rolled add their totals to the chosen effect.

Additionally, you learn the Glyph of Warding spell, and whenever you cast it or a ritual spell, you can use Giantish runes to empower it, and you may cast the spell without expending a spell slot and with half the casting time if your are working in a space that is at least a 10 foot square space or surface.

Gigantic Magic

10th-level Giant Pact feature

At 10th level, and you have learned to cast the grandiose spells of Giant wizards and shamans of ancient days. Choose any spell on the Warlock spell list, or any spell of 5th spell level from the Wizard or Sorcerer spell list. You can cast that spell without expending a spell slot as long as you have a 20 foot square space to draw a huge size rune in the air. You may use this feature once before you must finish a long rest to use it again.

Additionally, whenever you make an Arcana check to identify a spell being cast, you gain advantage on that check.

Rune of the Vast

14th-level Giant Pact feature

At 14th level, your pact with your Giant patron has revealed the wisdom and teaching of ancient Giantish runes that describe great magical processes of the cosmos itself; an understanding of which affords vast magical power. Whenever you cast a spell or cantrip with Rune Dice, you gain the following benefits:
Fire Rune: after you cast this spell, you add your Proficiency Bonus to the damage you deal with the next spell or cantrip you cast for the next 1 minute.
Frost Rune: the target of this feature also can only take an action, a move action, or a reaction (its choice) on its next turn.
Storm Rune: the target you moved is your choice of blinded or deafened until the end of its next turn.
Stone Rune: you gain a +2 magic bonus to your armor class until the beginning of your next turn.
Hill Rune: you can remove the blinded, deafened, poisoned, charmed, or stunned conditions from the target you restore hit points to.

Additionally, the size of your Rune Dice improve to d10's.

Lastly, if a Mystic Arcanum spell you cast deals damage, you may roll and expend any number of your Rune Dice and add the amount rolled to the total amount of damage dealt by that spell.