Brujo means male witch.
Ash's hand went through a bunch of different versions. It was initially supposed to be in a cylinder but it looked magnified in the camera so they had to go with the wrapped up in the cloth version.
This episode marks the first time in the Evil Dead franchise that the "evil force" that makes the "HUMMMMMM" sound as it moves is actually shown.
In this episode, viewers find out that Ruby is Ruby Knowby, daughter of Professor Raymond Knowby and his wife Henrietta, as well as sister to Annie, all characters who perished during the events of Evil Dead II. Furthermore, Ruby is in possession of Ash's possessed hand from the same film.
The brujo keeps repeating "Buena buena medicina, Buena buena luz divina" which translates as "Good good medicine, good good divine light". The rhyme is better in Spanish.