So I am wanting to parent a particle effect to the Players Torso, though it only works when executed via a LocalScript. Anyway of doing it via a Script so it can be seen by all players instead of just the client?
Yes! You just have to use remote events. This isn't exact, but i'll run through it generally; In the localscript do something along the lines of:
event = game.ReplicatedStorage.Particles event:FireServer()
In a server script, preferably in serverscriptservice, put something along the lines of:
game.ReplicatedStorage.Particles.OnServerEvent:Connect(function(LocalPlayer) particles = game.ReplicatedStorage.ParticleName:Clone().Parent = LocalPlayer.Character.Head end)