It won't position the character?

Aw man, you were so close. The reason nothing happens if you are a human is because you need an end after the third if statement. Your code should look like this.

function module:SpawnCharacter(plr,char,data)
    local D = math.random(1,2)
    local S = math.random(1,6)
    print("D and S Active!")
    local HRP = char:FindFirstChild("HumanoidRootPart")
    if data.Race.Value == "Demon" then
        if D == 1 then
            local NewCFrame1 = game.Workspace.Spawns.DemonSpawn1.CFrame
            HRP.CFrame = NewCFrame1
            print("Spawned Char")
        elseif D == 2 then
            local NewCFrame2 = game.Workspace.Spawns.DemonSpawn2.CFrame
            HRP.CFrame = NewCFrame2
            print("Spawned Char")
        end
    else
         if S == 1 then
             local NewCFrame3 = game.Workspace.Spawns.SlayerSpawn1.CFrame
             HRP.CFrame = NewCFrame3
             print("Spawned Char")
         elseif S == 2 then
             local NewCFrame4 = game.Workspace.Spawns.SlayerSpawn2.CFrame
             HRP.CFrame = NewCFrame4
             print("Spawned Char")
         elseif S == 3 then
             local NewCFrame5 = game.Workspace.Spawns.SlayerSpawn3.CFrame
             HRP.CFrame = NewCFrame5
             print("Spawned Char")
         elseif S == 4 then
             local NewCFrame6 = game.Workspace.Spawns.SlayerSpawn4.CFrame
             HRP.CFrame = NewCFrame6
             print("Spawned Char")
         elseif S == 5 then
             local NewCFrame7 = game.Workspace.Spawns.SlayerSpawn5.CFrame
             HRP.CFrame = NewCFrame7
             print("Spawned Char")
         elseif S == 6 then
             local NewCFrame8 = game.Workspace.Spawns.SlayerSpawn6.CFrame
             HRP.CFrame = NewCFrame8
             print("Spawned Char")
        end
    end
end

The reasoning is that the "else" statement that should be for the first if statement was actually for the third, the false indentation probably threw you off. Good luck with your game.