Glaive

A glaive was a reach weapon in the pole arm family.

Description
The glaive was a pole arm that, in its basic form, was a large knife mounted on a long pole. The blade was often augmented with a back spike, perpendicular to the blade or angled forward. An average glaive cost 8gp and weighed 10lbs (4.5kg).

Use
The glaive was a two-handed melee weapon with a 10 foot (3 meter) reach. Because it was a pole arm, it couldn't be used to attack adjacent foes. They were most effective in large numbers in a phalanx, or when they could be set against a charging opponent. Even though the tip of the blade was sharp and the back spike could be swung to penetrate armor, the glaive was considered a slashing weapon.

Realmslore
Bearded devils were known to carry sawtooth glaives.

Notable glaives
The tiefling warrior Havilar carried a glaive she referred to as "Devil Slayer".