Trait 1: Folded Ambush

Trait Name: Folded Ambush
Description: When motionless, the Zanarth Reaver folds into a spherical form. While in this form, it has advantage on Dexterity (Stealth) checks and can remain undetected in dim light or mechanical environments. It can unfold as a bonus action.

Trait 2: Arc-Powered Frame

Trait Name: Arc-Powered Frame
Description: The Reaver's body is charged with unstable arc energy. When a creature within 5 feet of it hits the Reaver with a melee attack, that creature must succeed on a DC 13 Constitution saving throw or take 1d8 lightning damage.

Trait 3: Agile Machine

Trait Name: Agile Machine
Description: The Reaver does not suffer movement penalties from difficult terrain and has advantage on saving throws against effects that would cause it to be paralyzed or restrained.

Trait 4: Ancient Engineering

Trait Name: Ancient Engineering
Description: Detect Magic reveals transmutation and abjuration magic radiating from the Reaver’s core. If targeted by Dispel Magic, it must make a DC 13 Constitution saving throw or be stunned until the end of its next turn.

Action 1: Whirling Blade (Multi-attack)

Action Name: Whirling Blade (Multi-attack)
Description: The Reaver unfolds and slashes twice with its retractable blade.
Melee Weapon Attack: +5 to hit, reach 5 ft., one target.
Hit: 7 (1d8 + 3) slashing damage.

Action 2: Arcbolt Launcher

Action Name: Arcbolt Launcher
Description: The Reaver fires a crackling arc of energy from its inner chamber.
Ranged Weapon Attack: +4 to hit, range 30/90 ft., one target.
Hit: 9 (2d8) lightning damage. The target must succeed on a DC 13 Constitution saving throw or be unable to take reactions until the start of its next turn.

Action 3: Magnetic Recoil (Recharge 5–6)

Action Name: Magnetic Recoil (Recharge 5–6)
Description: The Reaver emits a pulse of reversed polarity, pushing enemies away. Each creature within 10 feet must succeed on a DC 13 Strength saving throw or be pushed 10 feet and knocked prone. Creatures wearing heavy metal armor or carrying metal weapons have disadvantage on the save.

Bonus Action 1: Deploy Blade Arm

Bonus Action: Deploy Blade Arm
Description: The Reaver extends its hidden blade arm. Until the start of its next turn, its melee weapon attacks deal an additional 3 (1d6) slashing damage. If the Reaver has already deployed its blade arm, it may instead retract it as part of this bonus action.

Bonus Action 2: Fold Into Sphere (Roll Mode)

Bonus Action: Fold Into Sphere (Roll Mode)
Description: The Reaver folds into its spherical form, enabling high-speed movement. While in this form, its movement speed becomes 60 feet and it gains advantage on Dexterity (Stealth) checks made to remain undetected. It cannot take actions or reactions until it uses a bonus action to unfold.

While in sphere form, the Reaver may move through enemy spaces but cannot end its turn there. If it takes damage while rolling, it must make a DC 10 Constitution saving throw or be forced to unfold immediately.

Reaction 1: Blade Parry

Reaction: Blade Parry
Description: When a creature the Reaver can see targets it with a melee attack, the Reaver may add +2 to its AC against that attack. If the attack misses, the attacker takes 3 (1d6) slashing damage as the Reaver deflects the blow with its spinning blade.