Order of the Deep One

The Order of the Deep One is the most mysterious of the orders, the order was founded deep in the Underdark. Deep Ones use the eldritch powers granted to them by their master, the Deep One, the eldritch god of the Illithid of Del'nasra (my homebrewed world). Some will purposely allow their bodies to be experimented on by the illithid to take on some of the traits of their master, while others will expose themselves to dangerous eldritch horrors and magics to better understand the elements and magic they're playing with.

Because of this, the few Bloodhunters that exist in this order appear corrupted in some form, such as small tentacles growing out of their bodies, and more mutated, illithid looking features.

Boon of the Deep One

Starting when you choose this archetype at 3rd level, you begin to adopt the traits of the Deep One. You gain a Swimming speed of 30 feet, and you also gain the Amphibious trait found below if you do not have them already. You also learn to speak, read, and write Deep Speech if not already known.

You also learn the Eldritch Blast cantrip.

Amphibious. You can breathe air and water.

Eldritch Transformation

Upon choosing this archetype at 3rd level, you begin to learn to control the eldritch powers that have latched onto your soul. As an action, you can cause black, kraken-like tentacles to erupt from your body. You can use this feature twice. You regain expended uses when you finish a short or long rest. This form lasts for 10 minutes. While in this form you gain the following features:

You can speak, use equipment, and wear armor in this form. You can revert to your normal form earlier by using an action on your turn. You automatically revert to your normal form if you fall unconscious, drop to 0 hit points, or die.

Hide of the Deep One. Due to the eldritch tentacles coiled around your form, you gain a +1 bonus to your AC. Your skin also gains a slippery, slimy texture. Creatures have disadvantage when trying to grapple you.

Tentacles. Your tentacles are considered a single weapon in regards to your crimson rite feature. You can use Dexterity instead of Strength for the attack and damage rolls of your tentacles. When you use the Attack action with your tentacles, you can make another attack with your tentacles as a bonus action.

Your tentacles deal 1d6 bludgeoning damage. This die increases to 1d8 at 11th level, and 1d10 at 18th level. When using your tentacles as an attack you can choose to have the target make a Strength DC of 12 + your proficiency bonus or they become grappled.

Eldritch Horror

At 7th level, your swimming speed increases by 10 feet. You can also now walk up walls, and upside down on ceilings while using your Eldritch Transformation. You can now also cast Black Tentacles as a 4th-level spell as much as your Wisdom modifier per Long Rest.

Master of the Deep

Starting at 11th level, you can now take on the form of an Illithid (Mind Flayer) as an Action. This uses both of your Eldritch Transformations and replaces the traits of your Eldritch Transformation while transformed.

You gain the abilities found on the Mind Flayer page in the Monster Manual. This form lasts for 1 minute. You can speak, use equipment, and wear armor in this form. You can revert to your normal form earlier by using an action on your turn. You automatically revert to your normal form if you fall unconscious, drop to 0 hit points, or die.

Illithid Devotion

Beginning at 15th level, you’ve become more accustomed into taking the shape of an Illithid. Your Master of the Deep feature now only uses one of your Eldritch Transformations, and can now be activated as a Bonus Action. This form now lasts for 10 minutes.

Lord of the Deep One

At 18th level, you have conquered the eldritch powers that reside within you. You can now take on the shape and traits of an Alhoon using your Master of the Deep feature. You gain the abilities found on the Alhoon page in Volo's Guide to Monsters. This form lasts for 10 minutes. You can speak, use equipment, and wear armor in this form. You can revert to your normal form earlier by using an action on your turn. You automatically revert to your normal form if you fall unconscious, drop to 0 hit points, or die.