The Reapers may be small in numbers but they are obviously strong in spirit. That can be attributed to the group’s leadership. The team is headed up by an older man named Pope (Ritchie Coster), who we learn was the leader of the mercenary operation that they all worked for after they left the actual military.
Throughout the episode, we see first hand what an encouraging, yet exacting, leader Pope is. The Reapers do think of each other as family and Pope is certainly a stern father figure for the group. When Daryl finally gets the chance to meet him, he also learns that there is a strong religious aspect to their devotion.
Pope tells Daryl a story about how the Reapers’ religious dogma came to be. During a series of bombings after the fall of civilization, Pope’s squad took shelter in a church. When the bombings stopped, everything around them was totally incinerated. The church, however, was intact and everyone inside made it out without so much as a burn.
To Pope and his followers, that was a sign from God that they are chosen. This extreme faith makes them all the more terrifying a foe to deal with. If they sincerely believe that are God’s chosen ones, then they think of whatever actions they undertake as holy, even if those actions are ransacking and killing a community of innocents like they did at Meridian. The Reapers have a strong conviction that they are in the right to protect themselves and secure resources, which explains their merciless and violent approach to dealing with other communities. It also means they aren’t afraid to fight and die for their cause.