Only four DmC: Devil May Cry collectibles can be found while playing Mission 6: Secret Ingredient and throughout the following video game guide, you will be able to find their exact locations.
DmC: Devil May Cry Secret Ingredient, is relatively a short mission; however, at the end of the level a new boss awaits while the DmC Secret Door unlocks a challenging side-mission.
Secret Ingredient is unlocked as you continue to go deeper into the factory where the soft drink known as Virility is produced.
Mission Name: Secret Ingredient
Secret Doors: 1
Lost Souls: 2
Key #1 (Copper)
The first collectable in DmC Mission 6, is a Copper Key located in the starting area. Make sure that as soon as you gain control over Dante your turn around, approach the edge of the tunnel, and look down.
The key should be on a platform below your position.
Lost Soul #1
The first DmC: Devil May Cry Lost Soul in Secret Ingredient must be collected in the tunnel you enter, during the race against time. For this part of the mission, you have to reach the other side before the time runs out.
To do so, try to avoid fighting the Demons. Eventually, while you run towards the exit point, you will reach several floating platforms that Dante must pull in order to advance.
Once the platforms have been pulled, jump over the gap and turn around to see the Lost Soul attached to another platform in vertical position. The first DmC Lost Soul in Mission 6 can be observed while facing the entrance of the tunnel (not the exit).
You can get it by launching Dante from one side of the tunnel, using a double jump and the Angel Boost. After you collect it, run towards the exit point and go through the round door on the left side of the main tunnel.
Lost Soul #2
The second and final DmC: Devil May Cry Mission 6 Lost Soul can be found after you safely exit the previous tunnels.
You can notice that Dante stands in a large hall with a large door on the other side. When you enter the hall, turn left and attached to a pillar you should see the second DmC Soul.
Get it, and approach the door without going through it.
Secret Door #1 (Copper)
The only Secret Door in DmC Mission 6 is a Copper Door located on the left side of the large entrance that takes Dante to the Succubus.
The Secret Door can be observed while standing in front of the said entrance, by turning to the left; and it can be accessed using the Angel Boost Ability.
When you open the door the DmC: Devil May Cry Copper – Rapid Descent Secret Mission will be unlocked.
To finish DmC: Devil May Cry Rapid Descent challenge you have to use the Angel Boost and jump from one platform to another as quickly as possible. Make sure you hit all targets by the time you reach the bottom of the area.
At the end of the sixth mission the Succubus awaits, and you have to defeat the demon boss in order to unlock the seventh DmC: Devil May Cry mission, named Overturn.