You have made a pact with a Titan from the outer planes. Titans are the largest of true giant races, and ranked highest on the Ordning. Many titans were capable spellcasters or psionicists.

Beings of this type include Lanaxis, Omo, and Rammaq.

Titan Spirit

As a bonus action, you may empower your presence to rival that of a titan. This form lasts for 1 minute or until used again. While empowered, you gain a bonus to your HP maximum equal to 8 multiplied by your warlock level (for example, a 5th level warlock would gain 40 extra to their HP maximum), you also heal for that same amount when activating this ability. Also while empowered, whenever a hostile creature starts its turn within 60 feet of you, it must make a Wisdom Saving Throw against your spell save DC. If the creature fails, it perceives you to be the most dangerous creature around, and has disadvantage on attack rolls against anyone other than you. When this empowerment ends, your HP maximum returns to normal.

You may use this feature once per short rest.

Bonus Spell

The Enlarge/Reduce spell is added to the warlock spell list. You always have this spell prepared and it does not count against the number of spells you know. Additionally, you may cast this spell once per long rest without expending a spell slot.

Giants Resilience

You are imbued with the hardiness of giant kin. While empowered by your Titan Spirit, your AC gains an extra +1. This bonus increases to +2 at 10th level, and +3 at 14th level. Additionally, when you first gain this feature, you may pick one of the following damages to be permanently resistant to: Cold, Fire, Lightning, or Thunder.

Fuel the Flames

Whenever a creature fails their wisdom saving throw against your Titan Spirit, you heal 1d8 hit points.

Earth Shatter

Once per short rest you may momentarily increase your mass to that of a giant and stomp the ground. Doing so causes all creatures on the ground within 30 feet of you to make a dexterity saving throw against your spell save DC. Any creatures who fail are knocked prone and take 8d6 bludgeoning damage. Creatures that succeed are not knocked prone and take half damage.