Merrow Bloodline

Merrow are Merfolk who were twisted into monstrosities by the Abyss long ago. The blood of these Merrow somehow flows through your veins. Due to the connection to them, you gain powers of the ocean, and to a lesser extent the Abyss. Due to the nature of Merrow, most of these sorcerers do their best to remain secret, as Merrow have been known to drag sailors to their doom. 

Merrow Inheritance

Due to the aquatic nature of Merrow, you are able to breathe normally in both air and water. Due to this aquatic nature you also have a swimming speed equal to your walking speed. Finally, due to the demonic origins of Merrow, you inherently know how speak, read, and write Abyssal. 

Merrow Magic

Your connection to both the Ocean and the Abyss makes your magic unique. You have a slightly expanded spell list, which is shown below. Note that you are not automatically able to cast these spells. 

Additional Spells

• Create Water/Destroy Water (1st level)
• Pass Without Trace (2nd level)
• Bestow Curse (3rd level)
• Black Tentacles (4th level)
• Maelstrom (5th level)

When you cast a spell of 2nd level or above from this expanded list, or a spell of 2nd level or above that directly interacts with water (ex. Tidal Wave, Watery Sphere) you can refund 1 expended spell slot of a lower level. The highest level of spell slot this can refund is a 5th level spell slot. 

Command of Waves

At 6th level, you automatically learn the 3rd level spell Tidal Wave. This doesn't count against the number of spells you know. Additionally, if you are fully underwater, you can draw upon your sorcerous power to bend and move the water around you. As a bonus action, you can spend 1 sorcery point to grant yourself or a creature within 30 feet of you 60 feet of swimming speed until the end of their next turn. 

Aquatic Attunement

At 14th level, you can cast the 4th level spell Control Water once per long rest without having to spend a spell slot, however note that Control Water is not a spell you know and thus you cannot cast it using spell slots. Despite this, you can refund spell slots of 3rd level or lower when you cast Control Water in this way. Additionally, you have now acquired the knowledge of how to speak, read, and write Aquan. 

Oceans Dominion

At 18th level, your power has almost fully developed, and your power over water and the ocean itself is incredible. By drawing upon your wellspring of sorcerous power, you are able to display truly spectacular displays of control over water and waves. By spending 8 sorcery points, you can cast the 8th level spell Tsunami (see PHP). Additionally, you can cast the 3rd level spell Wall of Water by spending 2 sorcery points. Even though you are not normally casting a spell with either of these options, you can still refund expended spell slots with the feature granted by Merrow Magic.