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This particular coven operates as a powerful and widespread enterprise focused on accumulating power to direct the world in ways that align with their interests. This group operates similar to HYDRA or COBRA, recruiting members mostly from young people seeking power in society, with the intention of using them to expand the coven's interests. These individuals may rise in the hierarchy due to their successes and eventually become key members and important players. Witches gain more power through a dark ritual, which steals the life force from an unwilling victim and adds it to their own, making their magic stronger. Rituals are performed with a circle of 5, with each witch sharing in the power gained. This means that a young witch will join the coven in the hopes that, one day, she will be promoted high enough to start performing such rituals to eventually become a goddess.
Organizations like this operate like pyramid schemes, with the top echelons of power gaining the most energy from the ritual, and trickles down from there. Lets say the leaders and most advanced members share 60% power boost amongst themselves, the mid-tier level gain 30%, with the lowest getting the smallest 10%. This sharing of power evens out automatically once the ritual is complete, as everyone in the coven is connected through mystical oaths, which eliminates the problem of cheating anyone. However, this creates another issue.
Organizations like this need to grow and reach into different avenues of society to expand their power base. However, the amount of power that each member receives from the split of energy gets smaller as the pool gets bigger. Say the cult starts out with 100 members, with each tier getting the share of power according to their rank. With more people in the pool, that percentage decreases because it needs to be shared among more people. Smart interns who realize this would be less motivated to bring in more members because their share of power, as small as it is, gets smaller. Opportunistic members will then bump off other colleagues to decrease the pool, letting them get stronger.
I need a way to get members to expand the power base of the group instead of only thinking about their individual self-interest. How can I make this possible?
EDIT: My other question was about preventing members who are already apart of the organization from stabbing each other in the back with constant betrayals in order to get to the top. This question is geared towards recruiting new members outside the organizationton to expand its power base. Based on the new parameters, I believe that the question is not a duplicate.