Explaining

"Soul power has the power to corrupt any type of soul. Whether they are pure, evil, malicious, vengeful. It brings their inner greed out and corrupts them from the inside out. And if those people with corrupted souls kill someone. Then the dead rises." Adrian explained.

"Just like zombies?" Alex asked.

"No. Zombies are weak. They don't have speed. They don't have greed. They only have an infinite hunger. Except that they don't feel any pain, killing them isn't that difficult." 

"But corrupted souls are the total opposite of them. Although they do feel pain, they become ten times more powerful than they were while they were still alive." 

"For example, if a person can fight three people normally, then after being corrupted, fighting 30 people won't be a big deal. And if it's killing, then their speed rises even more."