Death cults hide behind a friendly, encouraging veneer of peace, tolerance or standing up for the unfortunate to get public acceptance and hide their darker nature.
They bring members in with promises of a higher purpose and unity and connection, using the vulnerability of disaffected and isolated individuals desperate for connection or community. Once they've been introduced and the seeds of dependency are set, they trap them in a web of vague confusing believes that put the threat of isolation or damnation in the event that they ever try to leave.
Death cults will claim any violence or harm done by their members as either self-defence, or the acts of unrelated extremists who do not represent. Their covert nature makes it incredibly difficult to verify if any faction is really a death cult or not, so there is no concise list of death cults - only a list of organisations that have been accused of being death cults.