Proceed with Caution: How To Train Your Dragon Series Review and Why We DNF
- MommaSaurus
- Dec 26, 2025
- 11 min read
Updated: 16 minutes ago
How To Train Your Dragon by Cressida Cowell
Quick Summary
Genre: Action, Adventure, Fantasy, Humor
Recommended Age: Upper Middle Grade/YA with Parental Approval
Possibly Concerning Content* (details below)
🤬 Language: Name calling and potty humor.
🛡️ Violence: Varies by book. See P.C.C.
❤️ Romance: None
‼️Heads-up: While we loved Books 1, 4 and 5, we advise strong caution with all others books. We DNF Books 3 and 8 and did not read Books 9 - 12.
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FAQs
Review:
I want to start this out by saying we really loved the first book in the How to Train Your Dragon series. We adore the movies and shows and so were anxious to dive into the source material. The books are nothing like the shows, so if you are looking for more of that content you may wish to search for the Ready to Read books, movie storybooks, or the Dreamwork's graphic novels.
The 'Book of Dragons' both the original and the new Live Action version are fantastic and great companions to the show and movies.
The first book did have some bullying but beyond that I felt like it was okay to continue. We really loved the fourth book.
Why We Did Not Finish The Series
Right around book 6, we began to sense a new theme within the How To Train Your Dragon book series. Things were getting less playful and humorous and becoming heavier and a tad darker.
We did finish book 7 and tried book 8 but we DNF that book within the first few chapters and have decided not to continue reading the series due to themes of the occult, slavery, and other content (detailed below). If you decide to read the series please consult other trusted resources.
📍Important Note: We listened in audiobook format so we cannot speak for any images that may be inappropriate in the physical copy of the books.
The audiobooks were narrated by David Tennant, who did a fantastic job. There was music and sounds effects but they were not overwhelming.
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Books in Series
Book 1: How To Train Your Dragon
📍Recommend with caution.
Review
The first book in the series is a lighthearted story about Hiccup getting his dragon Toothless, who is a small garden dragon who has an adorable stutter and a stubborn personality. Only Hiccup can speak Dragonese (the dragons call it Mud Tongue). Together with his friend Fishlegs, Hiccup and Toothless must face an enormous dragon threatening to consume all the Viking tribes.
We really liked this one but do note the 'Heads-up' section of the P.C.C. below.
Possible Concerning Content*
Click on dropdown arrows for details.
🤬 Language: Name calling and potty humor.
🛡️ Violence: Character death and injuries.
Possible Spoilers
There are mentions of blood
There is fighting.
A dragon blows up and guts are described.
Dragons are eaten
❤️ Romance: None
‼️Heads-up: Soothsayer. Vikings worship Norse gods.
Official Blurb
Dropdown for Blurb
"Hiccup Horrendous Haddock III, the quiet and thoughtful son of the Chief of the Hairy Hooligans, tries to pass the important initiation test of his Viking clan by catching and training a dragon. Can Hiccup do it without being torn limb from limb? Join his adventures and misadventures as he finds a new way to train dragons—and becomes a hero." - From Amazon
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Book 2: How To Be a Pirate
📍Recommend with caution.
Review
Hiccup, as part of Viking Training, has to learn how to wage war on land and sea. When he discovers a floating coffin with a riddle to a hidden treasure inside, Hiccup, Toothless and Fishlegs head out to the forbidden island of the Skulleons where they'll face pirates and dragons to find the treasure.
We did not like this one as much as the first book (see Heads-up in P.C.C. below) and you can skip it without really missing anything in the overarching story.
Possible Concerning Content*
Click on dropdown arrows for details.
🤬 Language: Name calling and potty humor.
🛡️ Violence: Character death and injuries.
Possible Spoilers
There are mentions of blood
There is fighting.
Dragons are eaten
❤️ Romance: None
‼️Heads-up: Soothsayer. Vikings worship Norse gods. Cannibalism. Slavery.
Possible Spoilers
The inside of a dragon's stomach is described in detail.
The tribe of Outcasts threatens to sell the main characters into slavery.
Hiccup's grandfather is a Soothsayer who practices fortune-telling.
The Vikings worship Norse gods.
Past: Canibalistic Outcasts
Official Blurb
Official Blurb (dropdown)
"When Hiccup finds a coffin at sea, he opens it to discover a riddle that will lead to the treasure of Grimbeard the Ghastly, the world's greatest pirate and Hiccup's ancestor. So Hiccup and his friends set out on a treasure hunt, determined to master the art of swordfighting. How else will they escape an island of murderous dragons, defeat a boatload of Viking pirates, and survive all the twists and turns their journey will bring?" - From Amazon
Book 3: How To Speak Dragonese
📍We do not recommend this book.
In the third book, Hiccup and friends face Romans (lead by Alvin the treacherous) who are determined to steal (and eat) every dragon on the Isle of Berk.
We were uncomfortable with the baby dragons being eaten alive so we did not finish this book.
Possible Concerning Content*
Click on dropdown arrows for details.
We DNF this book so our content warning is only for the first two chapters. We cannot speak for the rest of the book.
🤬 Language: Name calling and potty humor.
🛡️ Violence: Character death and injuries.
Possible Spoilers
There are mentions of blood
There is fighting.
Dragons are eaten alive by vikings
❤️ Romance: None
‼️Heads-up: Soothsayer. Vikings worship Norse gods. False god.
Possible Spoilers
A dragon believes he is a 'living god' and can be summoned by saying his name.
Hiccup's grandfather is a Soothsayer who practices fortune-telling.
The Vikings worship Norse gods.
Official Blurb
Dropdown for Blurb
"The story begins when Hiccup, his friend Fishlegs, and his cranky dragon Toothless get separated from their class during Boarding-an-Enemy-Ship practice. They accidentally board a prowling Roman galley intent on provoking war. When they rescue a tiny nanodragon, they uncover a plot to steal every dragon on the Isle of Berk!" - From Amazon
Book 4: How To Cheat a Dragon's Curse
📍Recommend with caution
Review:
This is our favorite book of the series! Fishlegs is bitten by a dragon and contracts Vorpentitis, a deadly disease with a ticking clock until death. There's only one cure: a mystical vegetable called a Potato. Thankfully, there might be one in a nearby Viking village. With the help of Toothless and Kamakazi, Hiccup will fake Sharkworms, Dommfangs, and crazy vikings to save his friend!
This felt like a Christmas tale and was such a fun listen/read. The action and adventure is gripping, the humor is funny and the twist is shocking!
Possible Concerning Content*
Click on dropdown arrows for details.
🤬 Language: Name calling and potty humor.
Possible Spoiler
Name calling
Potty humor
A Viking is named ‘Big Boobied Bertha’ and an ad asks, “will those boobies continue to go undefeated?”
🛡️ Violence: Character death and injuries.
Possible Spoilers
There are mentions of blood
There is fighting.
❤️ Romance: None
‼️Heads-up: Soothsayer. Vikings worship Norse gods.
Possible Spoilers
Hiccup's grandfather is a Soothsayer who practices fortune-telling.
The Vikings worship Norse gods.
Official Blurb
Dropdown for Blurb
"Reluctant hero Hiccup Horrendous Haddock III must rescue his best friend, Fishlegs, from the deadly disease Vorpentitis. The only cure is rare and almost impossible to find...a potato. But where will Hiccup find such a thing? He'll have to dodge the terrible Sharkworms, battle Doomfangs, and outwit crazy Hooligans if he's going to be a Hero. Again." - From Amazon
Grab a copy
Grab a copy on Amazon*
Grab a copy on Bookshop*
Book 5: How to Twist a Dragon's Tale
📍Recommend with caution.
Review
In the fifth book, Hiccup must find the Fire-Stone and take it back to the Volcano Island before it erupts, hatching thousands of Exterminator dragons and wiping out the Tribes.
We recommend this one as well, besides the regular warnings (see Heads-up in the P.C.C. below). It's a good action/adventure mixed with the humor the series is known for.
Possible Concerning Content*
Click on dropdown arrows for details.
🤬 Language: Name calling and potty humor.
Possible Spoiler
Name calling
Potty humor
A Viking is named ‘Big Boobied Bertha’ and they sing a song about, "strong are the breasts that crush without fear." A woman is described as having 'thunder thighs."
🛡️ Violence: Character death and injuries.
Possible Spoilers
A dragon is killed.
A lot of reindeer are killed.
A bunch of bad dragons are eaten in the end.
❤️ Romance: None
Possible Spoilers
There is a romance in the past between two characters but no physical intimacy is described.
‼️Heads-up: Soothsayer. Vikings worship Norse gods.
Possible Spoilers
Hiccup's grandfather is a Soothsayer who practices fortune-telling.
The Vikings worship Norse gods.
Official Blurb
Official Blurb (dropdown)
"The heat is on for Hiccup as he is called to save the day once again. Someone has stolen the Fire-Stone. Now that the volcano on Volcano Island has become active, the tremors are hatching the eggs of the Exterminator dragons! Can Hiccup return the Fire-Stone to the Volcano, stop it from erupting, and save the Tribes from being wiped out by the terrible sword-claws of the Exterminators?" - From Amazon
Grab a copy
Grab a copy on Amazon*
Grab a copy on Bookshop*
Book 6: A Hero's Guide to Deadly Dragons
📍We do not recommend.
In Book 6, Hiccup must sneak into a Viking library to steal their most sacred book in order to save Toothless from being banished. But the library is protected by dragons and the Hairy Scary Librarian.
We did not like this one mainly for the slavery and lying without repercussions.
Possible Concerning Content*
Click on dropdown arrows for details.
🤬 Language: Name calling and potty humor.
Possible Spoiler
Name calling
Potty humor
A Viking is named ‘Big Boobied Bertha’ and there are descriptions of lady parts, "her tremendous breasts heaved in surprise," and "even those boobies knew when they were beaten and they drooped in a distressed way."
🛡️ Violence: Character death and injuries.
Possible Spoilers
A dragon is killed.
❤️ Romance: None
‼️Heads-up: Soothsayer. Vikings worship Norse gods. Sacrifices. Slavery. Lying.
Possible Spoilers
There are mentions of a tribe possibly sacrificing people to a dragon. It's mentioned that this is most likely a rumor.
There are threats of slavery.
A man is sent to the slave islands to be a slave for a crime he did not commit. We are told not to feel bad because he is not a nice person.
There is a lot of lying in this book that is never reprimanded.
Hiccup's grandfather is a Soothsayer who practices fortune-telling.
The Vikings worship Norse gods and pray to them.
Official Blurb
Dropdown for Blurb
"To save his dragon, Toothless, from being banished, Hiccup must sneak into the Meathead Public Library and steal the Vikings' most sacred book. The Vikings keep books locked up and heavily guard. So to save his friend, Hiccup must brave the Hairy Scary Librarian, a dreadful army of Meathead Warriors, and the formidable Driller-Dragons. Will Hiccup live to see his next birthday?" - From Amazon
Book 7: How to Ride a Dragon's Storm
📍We do not recommend.
Review
It's the Inter-Tribal Swimming Race is here. But while the tribes race to win, Hiccup ends up on a slave-ship bound for America. Can he free the slaves and return to Berk in time to finish the race?
We were leery of this from the first chapter (see Heads-up) and though we finished the audiobook we did not like the darker turn the series seems to be taking.
Possible Concerning Content*
Click on dropdown arrows for details.
🤬 Language: Name calling and potty humor.
Possible Spoiler
Name calling
Potty humor
Big Boobied Bertha is described multiple times including “Big Boobied Bertha’s boobies are flapping so joyfully that they looked as if they would carry her off into the sky like a couple of hot air balloons.” “Bertha’s boobies drooped.”
🛡️ Violence: Character death and injuries.
Possible Spoilers
The deck is described as being bloody red
slaves threaten to eat the vikings livers.
A dragon is 'picked clean' where it's body rests at the bottom of the sea.
Slaves force a permanent 'slave mark' on Hiccup by using a sharp implement dipped in blue ink and digging it into the skin above his ear. He is forever tattooed and must hide it for the rest of his life or the other vikings will immediately take him into slavery due to the mark.
❤️ Romance: None
‼️Heads-up: Soothsayer. Vikings worship Norse gods. Curses. Slavery.
Possible Spoilers
There are slaves who 'put a curse' upon the ship. This is described in two different chapters that the slaves are ‘laying a curse on the ship, a curse on the voyage, a curse on every single Viking man, woman and child who was keeping them there" and that it makes Hiccup's hair stand on end.
The slaves make Hiccup swear on his slave mark that he will help them.
Soothsaying
Worship of norse gods.
Official Blurb
Dropdown for Blurb
"Hiccup Horrendous Haddock III, everyone's favorite reluctant Viking hero, has three months, five days and six hours to discover America, get back to Berk, save his father, battle Polarserpents, and win the annual Inter-Tribal Friendly Swimming Race. Can he do it?"- From Amazon
Book 8: How to Break a Dragon's Heart
📍We do not recommend. And we did not read any further books in this series.
Possible Concerning Content*
Within the prologue, there was already mention of a father killing his son and the bloody wars that followed. In the first chapter, there was a ghost that haunts the ocean searching for her lost child who will steal the heart of anyone she meets and take it below. Then, the Beserker tribe is apparently sacrificing people to a creature they call 'the beast.' At this point, we turned off the audiobook and decided we were finished reading the series.
📍*Possibly Concerning Content Disclaimer: I try my best to include all relevant content notes, or possibly concerning content, but I may not catch everything and/or you may feel things are concerning that I do not. Please research individually if you’re sensitive to specific topics/subjects! 📍
FAQs:
Q: Are the How To Train Your Dragon Books like the movies?
A: In our opinion, no. While the characters have the same names, and it takes place in Berk where dragons are tamed, that is where the similarities end. Check out YouTube for some comparison videos.
Q: Are the How To Train Your Dragon Books safe for my family to read?
A: Every family is different. Please read our Possibly Concerning Content for each book and reach out to others who may have finished the series who can give you more details.
Q: Is there heavy content in the How To Train Your Dragon Books?
A: While there is no language, or intimate romantic scenes, there is some heavier content including occult themes, violence, slavery, sacrifices, etc. They are very Viking. See our Possibly Concerning Content for each book for more details.
Pass it Forward
If you do continue to read the series, please leave reviews wherever you can that mention any possibly concerning content. Every family is different, but the more information we have the better we can decide what is best for our families.
Hopefully, we have given you enough information to decide if this series is right for your reader. That's why I created this blog, after all.
Until next time, stay Shelf-Aware
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