Children's fantasy series very similar to Narnia

Question

There is a series I read when I was a kid in the late 90s. The first book was literally a clone of The Lion, The Witch and the Wardrobe, plot points and beat for beat--kids get taken to strange land with talking animals and have to save it from evil witch.

The other books in the series were much different, though. In the second(?) book, the kids had to travel to some distant island and come back with some artefact. I distinctly remember them getting trapped by some sort of sentient mud monster called the "Earth-Trogg" in a cave before escaping.

In another book, they had to travel to the North Pole to stop penguins from completing some sort of ritual (the back of the book had "the penguins have stolen the north pole" as a tagline... which I found funny since it sounded comedic but the book was quite serious.)

In the last book, it was similar to Narnia's the Last Battle--all the enemies of our heroes have united, and they're trapped in an ancient fort on some mountain until saved by the "god" figure who rebuilds the world.

Answer 1

This is probably the Archives of Anthropos series. The books were written in open imitation of the style of the Chronicles of Narnia, including having plots that serve as Christian allegories. When I was in elementary schools, the first two books, The Tower of Geburah (1978) and The Iron Sceptre (1981)--the only ones that existed at the time--were a friend's favorite series. (I asked him about them on Facebook recently, and he still has them.)

The main characters are kids who are (as in the Narnia novels) transported to a fantasy world to save it. Several of the books involve quests to the Island of Geburah to retrieve various things.

The second book, The Iron Scepter, features adventures in the icy north, with talking polar bears and other animals, although I'm not sure about penguins. There's also a giant magical ice cream sundae to tempt one of the characters.

The last book, The Dark Lord's Demise, apparently published after the author's death (and according to some reviews on the Web, incompetently completed by other authors), does describe the end of the world, following the model of The Last Battle.

The books have been asked about here a couple times before: Ugly girl has heart frozen which makes her beautiful and Fantasy book I read in 2005; title contained "tower", children go through TVs to fantasy world .