As the name says, those are Loren's exclusive skills. The knockdown skill causes the enemy to fall on the ground, which makes him easily targetable and reduces his defense (maybe also AP if I use that system).
Rally - Increases all allies initiative by 5-10-15% - sustained
Knock Down - Attempts to knock down the target with base success chance of 10-20-30% - activated
No Mercy - Increases accuracy and damage by 10-20-30% if target is incapacitated (knocked down, stunned, etc) has 5-10-15% chances of killing him - sustained
Whirlwind - Special strike that hits all enemies around the character with 75-85-95% accuracy - activated
Like in other skilltree, the Knock Down+No Mercy combo can have devastating results, but those will probably be high level skills, and in general tougher enemies (bosses) will be either immune to knock down/stun or very hard to hit with those skills.
No mercy will work also in combination with other effects (stun for example). Anyway, will test in the game and see how it works!