As written, this feat has some undefined qualities and I'm interested in knowing more specific details. As of right now, I am unaware of any errata or comments from the devs' that clarify.

Deadhand Style, from Horror Adventures

> Benefit(s): While using this style, if you have at least 1 point in your ki pool, you gain a +2 bonus on saves against fear effects, and the DC of Intimidate checks against you increases by 4. As a swift action, you can spend 1 point from your ki pool to empower your unarmed strikes. Creatures hit with your unarmed strikes must succeed at a Will save (DC = 10 + 1/2 your character level + your Wisdom modifier) or become shaken for a number of rounds equal to your Wisdom modifier. This is a mind-affecting fear effect.

**Will hitting a creature multiple times cause an increase in severity of the fear condition?** Most effects that cause fear will list specifically that they don't (such as Intimidating to demoralize), but there's also the general *no stacking* rule, so I'm unsure.

[Related question][1]

[Another related question][2]


  [1]: https://rpg.stackexchange.com/questions/163084/deadhand-style-feat-duration
  [2]: https://rpg.stackexchange.com/questions/93144/do-shaken-frightened-and-panicked-replace-each-other-or-stack