" It's easy for a being of pure Law and Good to live up to these ideals, but you're a mortal.
The deva's speech about how important it is to keep trying to be good.
(Aside from being a Crowning Moment of Awesome in its own right).
Redcloak's What Have I Done speech belongs here.
The whole scene with V and Elan in the beginning?.
The hug Redcloak gets from his mom when we first see them.
The subversion comes when the newly zombified Barky eats a bird's brains, which entertains Xykon, cluing the reader into his psychopathic tendencies.
Subverted in Xykon's first appearance, we first see him as a four year old crying over his dead dog Barky when his sorcery powers activate and resurrects Barky, he is completely overjoyed.
Maybe he doesn't just express his love to her openly solely for being mage-material, but is unable to do this with Roy because of their history beforehand.
There's the other possibility - he worked this out after Eric's (recent) death.
However in Start if Darkness he is surprised by Sara saying children in the plural.
Made more fascinating by the fact that earlier in the book (but later chronologically), Eugene lies to Roy saying he never had another lead on Xykon, and if he had he would have walked out on them in a second.