Tiny Staffs of Power

Retributive Strike deals 160 damage (to the target that breaks it, or in this case, the target that it's attached to) on a successful save making even a Barbarian with 20 constitution who rolls maximum hit points die at level 5. Even if he has the Tough feat.

Note: if you are still worried about them surviving through some weird Abjuration-wizard/max-temporary-hit points-build, you could use Staff of the Magi for 400 damage but having 5 legendary magic items is more complicated than 5 very rare ones

A simple contraption with a metal piece pressed against the staff where the party's handlers could cast catapult (from a Ring of Spell Storing) or something on the piece of the contraption that snaps the tiny Staffs of Power and activate the Retributive Strike, while not strictly RAW, certainly makes sense realistically and thematically.

The government stole these magic items from a powerful Pixie conclave they defeated but lacks the spellcasters who would be able to attune to them so they use them for the only purpose they can by rigging them to this death machine.

... or something.

Perhaps the identify spell could be used by your party to realize just how screwed they'd be if they don't listen.

Tiny Staffs of Power

Retributive Strike deals 160 damage (to the target that breaks it, or in this case, the target that it's attached to) on a successful save making even a Barbarian with 20 constitution who rolls maximum hit points die at level 5. Even if he has the Tough feat.

Note: if you are still worried about them surviving through some weird Abjuration-wizard/max-temporary-hit points/relentless-endurance shenanigans, you could use Staff of the Magi for 400 damage but having 5 legendary magic items is more complicated than 5 very rare ones

A simple contraption with a metal piece pressed against the staff where the party's handlers could cast catapult (from a Ring of Spell Storing) or something on the piece of the contraption that snaps the tiny Staffs of Power and activate the Retributive Strike, while not strictly RAW, certainly makes sense realistically and thematically.

The government stole these magic items from a powerful Pixie conclave they defeated but lacks the spellcasters who would be able to attune to them so they use them for the only purpose they can by rigging them to this death machine.

... or something.

Perhaps the identify spell could be used by your party to realize just how screwed they'd be if they don't listen.

Tiny Staffs of Power

Retributive Strike deals 120 damage (to the target that breaks it, or in this case, the target that it's attached to) on a successful save making even a Barbarian with 20 constitution who rolls maximum hit points die at level 5.

A simple contraption with a metal piece pressed against the staff where the party's handlers could cast catapult (from a Ring of Spell Storing) or something on the piece of the contraption that snaps the tiny Staffs of Power and activate the Retributive Strike, while not strictly RAW, certainly makes sense realistically and thematically.

The government stole these magic items from a powerful Pixie conclave they defeated but lacks the spellcasters who would be able to attune to them so they use them for the only purpose they can by rigging them to this death machine.

... or something.

Perhaps the identify spell could be used by your party to realize just how screwed they'd be if they don't listen.

Tiny Staffs of Power

Retributive Strike deals 160 damage (to the target that breaks it, or in this case, the target that it's attached to) on a successful save making even a Barbarian with 20 constitution who rolls maximum hit points die at level 5. Even if he has the Tough feat.

Note: if you are still worried about them surviving through some weird Abjuration-wizard/max-temporary-hit points-build, you could use Staff of the Magi for 400 damage but having 5 legendary magic items is more complicated than 5 very rare ones

A simple contraption with a metal piece pressed against the staff where the party's handlers could cast catapult (from a Ring of Spell Storing) or something on the piece of the contraption that snaps the tiny Staffs of Power and activate the Retributive Strike, while not strictly RAW, certainly makes sense realistically and thematically.

The government stole these magic items from a powerful Pixie conclave they defeated but lacks the spellcasters who would be able to attune to them so they use them for the only purpose they can by rigging them to this death machine.

... or something.

Perhaps the identify spell could be used by your party to realize just how screwed they'd be if they don't listen.