Continuity mistake: When the two villagers throw the slab of meat on the rock for the creatures, it lands rib side up. A second later the meat is shown from a different angle, and now it is lying skin side up. (00:38:05)
Continuity mistake: When Ivy and Noah have a foot race to the resting rock, they run toward the house off the right a little, but the resting rock is way to the right, off camera, when they round the corner you can see the house they ran past probably more than a 100 meters away. If you notice the layout they are probably running toward the direction the cemetery.
Continuity mistake: Noah is sitting on the porch after stabbing Lucius, in the background is the house where Kitty and Ivy are talking about the marriage, it has a lantern on only to the right of the door. Presumably moments later Kitty and Ivy emerge from the house and suddenly there is a lantern to the left of the door as well.
Continuity mistake: When Alice Hunt speaks to Lucius at home after his request to the Elders, he is holding a skein of yarn as she winds it into a ball. As the shot changes to his back, and he gets up to open the box, all of the yarn disappears. He is not holding any, the length of yarn across the table has disappeared, and when Alice stands up, there is no ball of yarn or any other yarn visible.
Continuity mistake: When Ivy was talking to Lucius about how her older sister is spoken for, and how she is free to receive interest, her hand is on the other side of the pillar from her. When the angle changes, her hand is wrapped around to the front and she is almost hugging the pillar.
Continuity mistake: As Lucius is lifting the door to the basement to help Ivy down you can see the curtains moving to the right of the door. The next angle is at floor level and the curtains are dead calm.
Continuity mistake: In the scene where Lucius first goes into the woods, he picks a branch of berries off of a bush. The size of the branch and the number of berries on it is different when he is walking out of the woods. There are more berries and the branch is bigger than when he picked it. (00:26:50)
Continuity mistake: While saving Ivy, in one shot Lucius is shown beginning to let go of Ivy's one hand, and in the next shot, they are running and he is holding her other hand. The cut was too quick for them to switch hands.
Continuity mistake: As Lucius grabs Ivy's hand to rescue her from the creature and takes her inside, their fingers are interlocked, when it shows the closeup of the hands, it is a closed finger grip.
Chosen answer: There was no name, and I was not under the impression he was indeed the "go-to" guy. Other than dancing with Ivy and participating in the meet ritual, he was not seen in the movie at all.