Ursula (Tier 3)

Amphibious. Ursula can breathe air and water.

Special Equipment. Ursula wields a ruidium scimitar. If Ursula rolls a 1 on an attack roll made with the scimitar, she must succeed on a DC 20 Charisma saving throw or gain 1 level of exhaustion.

One with Shadows. When Ursula is in an area of dim light or darkness, she can use her action to become invisible until she moves or takes an action or a reaction.

Multiattack. Ursula makes two Ruidium Scimitar or Acid Bolt attacks. She can replace one attack to cast a spell.

Ruidium Scimitar. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 17 (3d6 + 4) slashing damage plus 7 (2d6) psychic damage.

Acid Bolt. Ranged Spell Attack: +8 to hit, range 90 ft., one target. Hit: 19 (4d8 + 5) acid damage immediately and 3d4 acid damage at the end of the target's next turn.

Spellcasting. Ursula casts one of the following spells using a 5th level spell slot, using Charisma as the spellcasting ability (spell save DC 16):

At will: create or destroy water, thunderwave

2/day each: armor of agathys, arms of hadar, thunder step

1/day: summon elemental

Tentacle of the Deep (3/day): Ursula creates a 10-foot-long tentacle at a point she can see within 60 feet of her. The tentacle lasts for 1 minute or until she uses this feature to create another tentacle. 

When she creates a tentacle, she can make a melee spell attack against one creature within 10 feet of it. On a hit, the target takes 2d8 cold damage, and its speed is reduced by 10 feet until the start of her next turn. As a bonus action on her turn, she can move the tentacle up to 30 feet and repeat the attack.

Guardian Coil: Ursula’s Tentacle of the Deep can defend her and others, interposing itself between them and harm. When she or a creature she can see takes damage while within 10 feet of the tentacle, she can use her reaction to choose one of those creatures and reduce the damage to that creature by 2d8.