[Regalus]

Spell name: Weapon Throw
Spell Tree: Armed(Hidden w/ Unarmed)

What it does: An Attack and a 'self-debuff'

You throw your weapon at an enemy that causes an aoe. You get a debuff for it and 'lose' the weapon the same way unarmed disarm does but maybe not as much. Except, you're also mechanically considered unarmed.

So you can use any unarmed spells freely.