The elusive [Shadow Mist] spell and the mighty [Granite Wall] were in place as they worked in tandem to disrupt the group of stone trolls by bewildering illusions and infuriating obstacles. At the same time, Emery gathered and focused all his concentration to control the dozen [Shadow Root] he had summoned, trying to further obstruct and immobilize the trolls.
However, one root was simply not enough to hold one troll. With the level of strength those creatures inhibited, Emery would need at least half a dozen to completely stop one troll from taking any actions.
Luckily, the stone bridge where the challenge took place had limited space, only 8 meters wide. Thanks to that, only four to five trolls were able to attack the group at the same time from each side. Otherwise, Emery was sure they wouldn't be able to survive the onslaught of the dozen stone trolls.