Enemy of God (1997) is the second in Bernard Cornwell's Arthurian trilogy. It's longer and more episodic than the Sharpe books, and I confess in my current uber-busy state I like those tight timelines and compact page counts. But this book held my attention nonetheless. Derfel is an engaging narrator, and probably the nicest, sweetest protagonist Cornwell has ever created--maybe just to have a contrast with all the non-stop war and gloom and occasional human sacrifice!
I wouldn't quite say I have a problem with how Christianity is treated in this book. It's not like pagans come out looking wonderful, either, what with the human sacrifice and so on. But, still...I hope Celtic Christianity wasn't really much like it's portrayed here. Frankly, I haven't researched it much, but I love the Celtic prayers I've read, the wild poetry of them, and I'd like to think there was at least some real beauty of spirit and good wildness driving their authors.