Water Elementalist

Element Power.  The water elementalist has 16 points of element power available to power their abilities. All expended point of element power are regained at the end of a long rest.

Elemental Magic. The water elementalist is a 7th-level elementalist. Its spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). It has the following spells available from the elementalist class features:

Water Adept Cantrips (at will): ray of frost, frostbite, shape water

Water Aspect Spells: misty step (3 points), lesser restoration (3 points), tidal wave (4 points), wall of water (4 points), freedom of movement (5 points)

Corrosive Tide: The elementalist can spend points of element power to add 1d8 acid or cold damage to a damage roll for each point spent. A creature damaged this way must make a Constitution saving throw or have its AC reduced by 1 for 1 minute. 

Restorative Waves: As a bonus action, the elementalist can spend points of element power to restore 1d8 hit points per point spent to a creature of its choice within 30 feet.

High Tide: When the water elementalist deals acid or cold damage to a creature, it can spend a point of element power to force the target to make a Strength saving throw or be knocked prone.

Multiattack. The water elementalist makes two quarterstaff attacks. It can cast a cantrip that it knows as a replacement for one of these attacks.

Quarterstaff. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d6) bludgeoning damage, or 4 (1d8) bludgeoning damage if wielded with two hands.