Thalassa

2: Elemental Spells, Spirit of the Depths
6: Primal Tides
10: Profound Stillness
14: Embodied Tides
20: Transcendence

Elemental Spells

The following spells are always considered prepared for you, provided you have spell slots of a high enough level to cast them.

1st level:
2nd level:
3rd level:
4th level:
5th level:

Primal Tides

At 6th level you focus on the secrets of the tides and their meanings. Choose one of the following: 

Deep-Dwellers
You are able to call upon lesser spirits to animate the bodies of your fallen foes. If a creature that is Small or Medium dies within 10 feet of you, you can use your reaction to animate it, causing it to stand up immediately with 1 hit point. The creature uses the Zombie stat block in the Monster Manual. It remains animate for 1 hour, after which time it collapses and dies.

In combat, the zombie's turn comes immediately after yours. It obeys your mental commands, and the only action it can take is the Attack action, making one melee attack.

You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses of it when you finish a long rest.

Falling Tide
Your Spirit can sense when the tide is shifting and strike at the opportune time. Whenever a creature adjacent to your Spirit dies, you can use your reaction to allow it to move up to 10 feet without provoking opportunity attacks and make a Melee attack against a valid target.

Rising Tide
Your Spirit can rise to the occasion to protect you from harm. When you would be hit by an attack, if your spirit is adjacent to you, it can use its reaction to grant disadvantage on the triggering attack. If the attack fails to hit you, your spirit is hit instead.

Profound Stillness

At 10th level you manage to create a deeper link with your Spirit of the Depths. Choose one of the following or gain an additional Primal Flame feature you haven’t previously selected.

Calm Before the Storm
Your spirit's calm demeanor enhances your magics. Whenever you cast a spell while you are adjacent to your spirit, you can cast that spell as if it were one level higher then the spell slot used to cast it. In addition, when you cast a spell with a range other than self, the spell can originate from you or your wildfire spirit. 

Rippling Thoughts
Your spirit's mind is connected to yours. If you would lose your concentration, your spirit can use its reaction to start concentrating for you. While your Spirit maintains concentration, you cannot concentrate on anything else.

Embodied Tides

At 14th level you attune to a tide and how it intertwines with your life. You gain one of the following:

High Tide
When you fall, your spirit plunges in the depths to prop you back up. If the spirit is within 120 feet of you when you are reduced to 0 hit points and thereby fall unconscious, you can cause the spirit to drop to 0 hit points. You then regain hit points equal to the Spirit's current hit points and immediately rise to your feet.
Once you use this feature, you can't use it again until you finish a long rest.

Low Tide
When you fall, creatures and spirits of the depths grasp upon you to escape the endless sea and aid you in battle. When you are reduced to 0 hit points, two additional Spirits of the Depths are summoned into objects under your possession and will fight to protect you until you regain consciousness, after which they remain under your control for 1 hour.
Once you use this feature, you can't use it again until you finish a long rest.

Transcendence

At 20th level, your control of Thalassa's spirits and tides are unmatched. Your Spirit of the Depth never expires and fully heals during a short rest. Also, your spirit gains a new action, allowing it to create powerful waves that crash upon your foes. As an action, it can creates a 20-foot tall, 20-foot wide wave that travels 30 feet in one direction and then crashes down. Any Large or smaller creatures and objects in the wave’s path make an Anchor saving throw against your spell save DC. On a failure, a creature takes 4d8 bludgeoning damage and is carried with the wave. Any creature that succeeds on its saving throw takes no damage and is not moved.