There is right and wrong, there is good and evil. But the context of this is sometimes hard to explain when it comes to Sikhism.

Here is my view.

Yes there is Evil and there is Good. At this Age (Khal Jhug) Evil runs freely over minds. Evil is split into a two sections. Thoughts and actions. Both occur. Evil actions are easy for most humans to stop its the evil thoughts that take us down or off are spiritual paths. Most evil within the world is catergorized into 5 types according to Sikhism. Lust, Anger, Attachment, Greed, Pride. These 5 vices are the root cause for ones action until one surpasses these on his/her spiritual path.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-sikhi-sikhism/3126-sikh-concept-of-evil-devil.html

In Sikhism Evil is also describe as the moment ones thoughts breaks from Oneness with WaheGuru. A secondary thought other then WaheGuru is "evil" but this is on the final stages of the path.

Last type of evil is Karma. Certain events occur in life no matter how good, bad or any other reason. We must pay for some deeds in this life some in the next or some when we go to Dharam Raj.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=3126

Now as for the Devil. No Sikhism doesn't have a true devil like Christianity or Islam. The word Devil is mostly tied to the five vices as those are the devils in us that break us from our path.

As for "Does God battle against Evil, is Evil an intrinsic part of God's Natural Universe, or both?"

No battle occurs because the realization at the end is that at both ends of the spectrum there is WaheGuru no one else.