From LSWiki

Class: Close Combat Weapon Skills
Attribute: Agility
Pedagogy: Physical Training
Practitioner Term: Flail Fighter

The ability to use flails and similar flexible weapons, such as whips and scourges, in combat.  When using such a weapon, this
skill influences your ability to hit your opponent, the damage you inflict, how fast your attacks are, and how well you can use
your weapon defensively.

Development Information: The flail skill was created by Lost Souls; the source code was last updated Thu Mar 03 13:01:10 2016.

Notes

Trainers

Avalon: Bercilak
Wandering Lhethan Hagal
Kolond: Duthien (only trains dwarves)
Losthaven: Raelan Jax
Mycenae: Kyros
Shatterspire: Sthlar
Stillwater: Captain Roberts
Valathyr: Selendyl (Teaches elfish races only)
Xi Feng Ming: Shun Lang
Association:
Losthaven Guard: Commander Jonathan Tredwel
Guild:
Aisenshi: Musashi
Hawkmen: Katar
Knights of the Round Table: Sir Lancelot
Quest:
Corna Quests: Marshall Osaka