So what I'm trying to understand is what exactly pre-Tolkien orcs were like in regards to folklore. I understand that Tolkien has had a massive influence on how we conceptualize many creatures from different myths such as dragons, wargs, and dwarves, but in all these cases they existed in a defined form before Tolkien used them in his stories. Orcs seem to be a bit different because I haven't found one or a few myths where they exist as their own thing.
Were orcs even a single creature pre-Tolkien or did he pull from multiple sources to create his own amalgamation? Are there any myths where I can find them?