Yee-Dora, Forgotten Guardian of the Sea

Natural Spellweaver. Yee-dora can cast 1 Cantrip as a free action on their turn and has advantage on Concentration saves.

Spellcasting. The Forgotten Guardian of the Sea is a 2nd-level spellcaster. Its spellcasting ability is Wisdom (spell save DC 17, +6 to hit with spell attacks).
The Forgotten Guardian of the Sea has following spells prepared:

Cantrips (at will): Chill Touch, Frostbite, Ray of Frost

1st level (8 slots): Fog Cloud, Frost Fingers

2nd level (5 slots): Enlarge/Reduce, Gust of Wind

 3rd level (3 slots) Slow, Spirit Guardians

Staff Swing. Yee-dora swings her staff at the target elegantly yet with violent intent.

Staff of Sapping. Melee Weapon Attack: +5 to hit, reach 10 ft., 1 target. Hit: 16 (2d4 ) Bludgeoning damage, (2d4) Necrotic damage. Upon successful hit the user chooses one check/save for the target to have disadvantage on until the end of the attackers next turn.

Create Whirlpool

Creates a Whirlpool that moves in an L shape. Upon being hit by a whirlpool the pc must roll a Strength save with a DC of 18 or be restrained by the whirlpool and pulled under the water by 1/5 . if 5 whirlpools hit one pc they get fully pulled under the water and will drown after 3 turns.  Every additional whirlpool increases the Strength save DC by 2 each. (26 Max) The Save DC is cut in half if a PC takes their action to Help the restrained player. The PC makes a Strength save at the start of their turn and has disadvantage on concentration saves while in the whirlpool. Whirlpools can pick up rubble spinning it around violently to deal force damage to anything it passes or gets stuck inside. Small rubble is 1d8 damage,  Medium is 3d8, Large is 5d8

When hit in melee range

Wave Crash. Creates a wave of water around herself that spreads out 30 ft. Players in melee range of 5-10 ft must make a CON save with a DC of 15. Players within 11- 30 feet must make a CON save with a DC of 14. A player who succeeds the CON save takes 3d6 force damage. A player who fails the same takes 3d6 force damage and is knocked back to the end of the waves ripple (30 ft from Yee-dora straight back) and knocked prone.

When a Player leaves the water

Ocean's Grasp. Creates a hand out of the water with 15 hit points and 13 AC. Resistance to non-magical attacks. And 35 movement speed. Can only stay outside the water for 1 round or it disperses. Cannot Dash.

Upon reaching a player the Ocean Hand will attempt to grapple them with a STR save DC of 15 and pull them back into the water with the remainder of its movement speed. The player will remain grappled until they succeed on the Strength Save which they may take at the end of each of their turns or the hand is destroyed or they are brought into the center of the water and the hand dissipates back into the sea.

Yee-dora may use 1 legendary action at the end of a players turn.

Unworthy... Whips up 5 whirlpools. Whirlpools always go last in the round.

Drown! Yee-dora points at a player and all Whirlpools and Ocean Hand's get to move once towards that player and will continue to follow them.

Falter! Yee-dora causes the water to erupt under a player they must roll a DEX save (DC 17). On failure they take 3d4 force damage and are knocked prone. On success they take no damage and no additional effects. (if used on ice the damage increases to 3d6)

Begone! A large wave crashes forward  from Yee-dora away from the statue. All whirlpools move 5 ft to the left if hit by the wave. All players hit must roll a CON save with a DC of 15. On failure they take 2d6 force damage and are knocked back 15 feet. On success they take half damage and no additional effects.
After this ability is used the water level rises and Players/Yee-dora must swim (cannot be used on the ice)

Judgement! Can only be used after "Begone!" has raised the water levels. Yee-dora stops moving and is restrained as a large Tornado whips up around her. All ranged attacks MADE OUTSIDE OF THE TORNADO on Yee-dora have disadvantage to hit even though she is restrained. Abilities and spells that require saves are unaffected. Yee-dora spends her next TWO turns casting and cannot use action, bonus action or reactions. She may still use legendary actions. 

In order to get into melee range with Yee-dora, players must break through her Tornado (Strength Check of 16 to break through) and must succeed on a CON save (DC18) before each melee attack inside the vicious center of the Tornado to keep their footing. Failure results in attacking with disadvantage and being whipped back out of the Tornado after the attack.

After being hit while casting this ability Yee-dora must roll 1d20 and the spell will either continue being cast or fail causing the Tornado to disappear depending on the roll.
1 Hit = DC 11
2 Hits = DC 13
3 Hits = DC 15
4 Hits = DC 17
5+ Hits = DC 20

Upon Successful casting of this ability Yee-Dora unleashes the tornado which moves forward from her in a 60 foot cube until hitting a wall. Anything hit by tornado will be restrained and take 3d10 force damage at the start of their turn and will continue to do so until the tornado goes away. The tornado moves 40 feet each round and the start of the round and will go away if Yee-dora is defeated.

The water level will reset back to normal if the casting is a success but will remain raised on a failure.