Brave. The assassin has advantage on saving throws against being frightened.

Diving Suit. The submersible assassin wears a strange, metallic suit that grants its wearer a swimming speed of 40 ft., AC of 20, the ability to breathe underwater, as well as the following traits and actions. The suit itself can be attacked or targeted with applicable spells that target objects. It has an AC of 20, 250 HP; immunity to all conditions, acid, cold, necrotic, poison, and radiant damage. The suit is resistant to all other damage types, and is only rendered broken at 0 HP, at which point it only needs repaired.

Evasion. If the assassin is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, the assassin instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.

Magic Resistance. The diving apparatus has advantage on saving throws against spells and other magical effects, and granting the same benefit to it's wearer.

Apparatus Spellcasting. The diving suit is a 13th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). It has the following wizard spells prepared:

Cantrips (at will): blade ward, fire bolt, light, minor illusion, thunderclap

1st level (4 slots): alarm, burning hands, color spray, disguise self, shield

2nd level (3 slots): darkness, enlarge/reduce, warding wind

3rd level (3 slots): catnap, counterspell, leomund's tiny hut

4th level (3 slots): banishment, fire shield, stoneskin

5th level (2 slots): bigby's hand, creation

6th level (1 slot): contingency

7th level (1 slot): whirlwind

Multiattack. The submersible makes three melee attacks of any combination; or it makes one of these attacks and casts a spell with its Spellcasting.

Claw Arm. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) bludgeoning damage and the target is grappled by the suit's claw arm, which can only grapple one target at a time if it is Large or smaller. The DC to escape this grapple is 16.

Longsword. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) slashing damage.

Poisoned Harpoon Gun (1/Day). Ranged Weapon Attack: +10 to hit, reach 120 ft., one target creature, object, or location. Hit: 18 (4d8) piercing damage. If the target is a creature, it makes a DC 18 Constitution saving throw. On a failure, they take 17 (5d6) acid and 17 (5d6) poison damage, or half as much on a successful save.

No matter the target, the harpoon sticks where it lands if it scored a successful hit. The submersible suit owner then has the option to either:

• Reel in a Large(or smaller) creature/object it has stuck toward itself 60 ft.
• Move the attached suit towards the struck target 60 ft.

At the start of the suit's next turn, it finishes this movement in either chosen direction, with the target being reeled or the suit arriving 120 ft. away, unless the rope or harpoon was interacted with.

Parry. The Submersible assassin adds 4 to its AC against one melee attack that would hit it. To do so, the assassin must see the attacker and be wielding a melee weapon.

Legendary Action Uses: 2. These legendary actions are granted by the suit, and only when the assassin is outnumbered heavily (3:1). Immediately after another creature's turn, the submersible can expend a use to take one of the following actions. The assassin regains all expended uses at the start of each of their turns.

Attack. The submersible assassin makes a melee weapon attack of their choice, against one target within its reach.

Move. The submersible assassin may move up to their full movement speed.