The Invader plays a very important part in the game. The Invader is basically the decoy of the group, constantly shifting positions and tricking the enemies into attacking him/her rather than focusing on his/her team's Striker.
Write in your dream build for a Invader Here!
Pistol/SMG/Semi-Rifle (Your Choice)
This build is based on TF2: The Spy character
Belexar's Build v1.0:
Plasma Sword: The dash is escential if you have to work as the backup striker.
Gauss Rifle: A personal favorite, quite lethal if you handle it well.
Revolver: Deadly at mid and close range, also good for messing with twinners
Anchor: I prefer it over the wings because of its speed.
The clothes are up to you.
Belexar's Build v2.0:
Plasma Sword: Can kill an enemy in two strikes if improoved. Taser Sword FTW!
Heavy Machine Gun: Mow down the enemy likes! DAKKA DAKKA DAKKA!
Revolver: To stop twinners in their tracks. Also, its always fun to point-blank the head of an unsuspecting sniper.
Flying: Recently discovered to be an extremely good option for an invader, due to the angles you can get with it for the HMG.
Clothes are up to you, but I prefer the Captain Guard.
Monét's Build Although I am not great at using the Invader, I find that a good use of weapons and skill can bring good use to a novice Invader. When I go for an Invader, my build is more like that of an Assassin, making it easier to land sneaky kills.
Spy Dagger: Although not seen as something most players would use for an Invader, when paired with an Invisibility skill and a high enough attack increase, you can assassinate any defender in a split second without being noticed. The tactic to use this properly on a defender though, is to get behind them and use the stab attack.
Revolver: A great weapon when known how to use, mostly for mid to long range. The power of the Revolver makes it easier again to take down a defender, and especially useful for, like how Belexar says, take down those who use the twin daggers, as you can avoid their jump attack whilst being able to fire.
Light Machine Gun: Although not as high powered as the Heavy Machine Gun, it is slightly faster making it able to fire off more shots with less cooldown, which is great for storming the enemy base and being a distraction for your team's Striker.
Skill: Invisibility: I find Invisibility to be a good skill to use alongside an Invader made with the weapons in this build, because then you can approach a Defender without being seen and killing them quickly, and also approaching a sniper and killing them without the chance of being noticed.
Use this combination with caution, because as soon as you strike, Invisibility stops working, so be prepared to have to attack more members of the opposing team. Suggestion is is that you should attack whoever has a weapon that poses more threat to your build, for instance, a Rail Gun-using Sniper, as once hit with their Rail Gun, you are practically rendered useless. Point-blank them, and then deal with the defenders with your guns. Another recommendation is recharge your SP; after the Sniper and attack the Defenders then as Invisible.