Which race is more evil - goblins, orcs, or something else?

I'm writing a novel where I want to subvert readers' expectations and introduce a race that is initially considered the big threat to the world that everyone needs protecting from. Later in the story, I will gradually reveal them to be a potential ally.

For the story to work, they must be:

• Unable to fly.

• Not undead.

• Roughly humanoid.

Other than that, I've got a lot of range.

I have thought about orcs, goblins, another race from myth, or inventing my own. The advantage of orcs and goblins is everyone knows what they are and has an immediate impression of it. The disadvantage is that everyone's preconceptions will be slightly different.

Hence my question, when you think of orcs and goblins, which do you consider more vicious? Are there any other races that really evoke evil when you think of them? Or do you think it would be better to create a new race and sow the preconceptions in the manuscript as I write it?