The Noldor army is not going to be defeatable on equal terms. If Noldor army has 450 troops just stay clear of it or let your allies be defeated. The Noldor are meant as more late-middle or end-game should you decide to fight them. If your Empire gets together a Marshall army of say 3,000 strong, you could try to let them auto-calculate the battle. If you find smaller groups of Noldor, you can take them down with a good sized army(say if you have 4x or 5x their numbers then just auto-calc. Don't forget that you can befriend the Noldor by helping them out and releasing their prisoners. Their friendship can be very useful when you start your own kingdom.

As for the Demon army, the most dangerous part are the actual Demons who have the wings and horns. You will need piercing weapons to get through their very strong armor. Or better yet, get good with a bow and headshot them. You will have to have lots of ammo in your stash that you go back and pick up when you run out. Try and fight near your stash and ally spawnpoints so you get reinforced quickly and have easy access to all the ammo you brought with you.

Hey, where do you get guns? or whatever Firearms stand for?

thanks for the advice it will be helpfull