It took 95 kills for my group the first time - seems to vary pretty widely depending on your luck. I can also suggest killing boars for fastest / easiest kills. If you do go after boars, probably use tank to pull; their mechanic is effectively an aggro lock on a random hate list target - easy if only one on hate list when they cast is the tank.
Update: Two subsequent runs on skeletons near zone-in area took 74, and 75 kills to get the charms.
Edited, Mar 25th 2018 3:12pm by MaisCogar
Edited, Mar 25th 2018 5:14pm by MaisCogar