The Deryni series is an endless march of trilogies produced by popular fantasy author Katherine Kurtz. The first three - Deryni Rising, Deryni Checkmate and High Deryni - were published between 1970 and 1973.
The books chronicle the "adventures" of young King Kelson and his right-hand superman, Morgan. Both are Deryni - a race of more-human-than-human people with continuously astounding psychic powers.
Kelson is continually menaced (but never actually threatened) by a series of enemies - human, Deryni, ecclesiastical, familial, etc. However, between Morgan's awe-inspiring ability to generate new psychic abilities on the fly and other deus ex machina devices, there's not really anything approaching tension or concern.
Broad brushstroke failings aside, this series was also terrible in a lot of specific ways:
First, the setting is a combination of genero-Celtic and some sort of uber-Christian middle ages.
Second, the characters are all vaguely conflicted, unevolving and dull.
Third, nothing ever happens.
Fourth, the only plot thread that runs through all three books is resolved in an unsatisfying, frustrating, painful and badly-written way.
Fifth, and most important, magical duels take the form of two people squaring off and yelling rhyming poetry at one another. This even bores the author - that duels are written as two exceedingly painful pages of bad poetry and then conclude with a paragraph blandly stating that "more spellcasting followed". Poetry in fantasy is the bastard child of boring and pretentious - raised in the nursery of stupid and then invariably sent off to the school of badly written. And this isn't easily-escapable blocks of Tolkien-esque sing-song bollocks, Kurtz's poetry is what passes for conflict in these books. Lesson learned: when two Deryni fight, the only one that loses is the reader.
Also, don't read these books.
Note: According to the author bio, Kurtz is thoroughly involved in the Society of Creative Anachronism. No offense meant, but that certainly explains issue number 1 (as well as 3 and 5, come to think of it).
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