I certainly expected a demon fixated on causing trouble and generally being a bad guy, but Kiriel is quite the opposite. He experiences adolescence, and humanity for that matter, as a complete outsider. He savors every smell and sensation, and he makes Shaun a much nicer person to be around. He makes amends with Shaun's little brother, helps out around the house, and is truly grateful for the experience of being human. All good things must come to an end, as they say, and he realizes that the Unfallen (angels) and maybe even the Creator himself will put an end to his vacation any time.
This book was truly a pleasure to read. Not just because the writing is great, which it most certainly is, but also because Jenkins turns everything we imagine about "evil" on its head. Certainly Kiriel is subversive and steps outside the accepted order, but he is never malicious. As Jenkins herself writes:
...I like his irrepressibility. He's been cast into Hell for eternity, cut off from God forever, but instead of losing hope he either makes do, or comes up with another plan to try and get what he wants. I suppose what's sinful about him is that he can't or won't be humble, trusting, and obedient. But I rather admire the lack of those qualities when there's no cruelty, malice, or self-righteousness involved.
The only uplifting times are when, unsually after millenia of suffering, a single soul suddenly, for no reason that's apparent to me, decides that it's had enough, that it's paid the price for its wrongs, and it sort of twists itself inside out, shedding its misery to go free. It's a beautiful, memorable, and very rare event. It's a cool rush, a sweet atom of a movement in an eternity of heavy dark. But even that fine moment has its bitterness. In Hell, nothing is pure joy. There's sorrow in the moment of release, when the soul realizes that a true sin, once committed, can never be undone, and thus in one respect can never be paid for.