'That's for sure.' Dusk replied. 'You need it in your everyday life. If you have more time, instead, suggestion is a powerful tool especially when your host is asleep. Unlike us, all creatures lower their guard while they rest, even the undead.
'During their slumber, their mind is helpless and whatever you tell them, they'll mistake it for their own thoughts. Over time, the seed of doubt you plant will turn into a strong belief that you can nurture or prune as it develops.
'Another way to bend your host's will is to amplify and suppress their feelings while they are awake. This way…'
Kelia was supposed to study the power core of the Wayfinder while Dusk instructed Solus but she was too shocked to do anything but listen.