[DrillBIT]

The 2 "workers" at the beginning of episode 2 had the incomplete Sengoku Driver (missing the blade). They turned into the 2 Inves at the end (most likely used the seed on their own drivers).
Sengoku Driver extracts the life energy from the user, and transfer it to the lock seed. The lock seed converts the life energy to power up the Armored Rider and weapons. In other words the belts are sucking the users dry. Sengoku Driver will have only 1 user at a time, until they runs out of life energy.
Genesis Driver works the other way. It refills the user's life energy by taking the opponents'.
Sid and the DJ works together to promote the use of lock seeds. More people will sacrifice their lives without knowing what they did wrong.
The city has no intention of stopping the shipping of lock seeds. Civilians are pretty much test subjects, or nutrition for the mysterious forest.