Infestants are demonic parasites that search for a sutible host bodies, usually within animals and insects, but in the case of Devil May Cry 2 they take host within and Chopper and a Tank.
 Infested Tanks
Strategy: The strategy I used to use was to jump on top of the tanks and slash away at it, because the fireballs would never be able to hit you. But the machine gun after a while would start firing away at you. After some more experimenting, I realized that if you stand right next to the tank, and slash away there, the machine gun can't hit you, and the fireballs can't hit you either, basically saying that it is impossible for him to hit you.
- FIREBALLS: They launch large fireballs at you. Just dodge to either side to avoid them
- MACHINE GUN: Rapid firing machine gun. Just dodge to either side to avoid the bullets.
- WHITE BEAMS: Long slow white beams launched at you. Just dodge to either side to avoid them.
 Infested Chopper
Strategy: Not much of a strategy here, except that you can't use a melee weapon, another words you can't really use your sword, unless you use Devil Trigger, and fly close to the chopper. So just continue to dodge all of his missiles and attacks, and just shoot away with your firearm, to cause damage. Usually he is out of the screen and you can't see him, so you just got to realize when there is a missile coming down and dodge away.
- MISSILES: A pair of missiles is shot from the chopper towards you. I suggest to just dodge them, by rolling right or left. If you want you can shoot them, they will blow up with one shot, but it is easier to just dodge. If they don't crash into an obstacle they can and will find their way around to come back after you.
- WHITE BEAMS: The chopper can send down a mass of white beams in a pattern towards Dante. To avoid these just continue shooting at the chopper and walk away.
- ACHINE GUN: The chopper shoots at you with his machine guns. Just dodge the place where the machine gun is fired to avoid the damage.