ref: Uoguide UOwiki
In monsters the skill works properly, but if you target players it makes nothing and it was supposed to function similar to monster and with a slow effect (if it is a player). I tested on a char with and without guild in both dont worked.
even in the trueuo code (FrenziedWhirlwind.cs) it appears the slow effect:

wep used: Wakizashi
Char Skills:

tested with and without a guilded char. heres the test on a pet and player, after in some mobs:
In monsters the skill works properly, but if you target players it makes nothing and it was supposed to function similar to monster and with a slow effect (if it is a player). I tested on a char with and without guild in both dont worked.
even in the trueuo code (FrenziedWhirlwind.cs) it appears the slow effect:

wep used: Wakizashi
Char Skills:

tested with and without a guilded char. heres the test on a pet and player, after in some mobs: