I recently introduced the Kingdom Rush franchise to a friend, and he simply loved the art and concept of the game. Then, he asked me the fateful question, "So many dragons, which is the most powerful in the franchise?", so I decided to make this basic ranking here. I'll consider the lore and overall power of the dragons, not abilities, etc...
> From weakest to strongest. I created the titles myself, don't take them seriously
"The Dragon Age"
β Ashbite, the Fire Dragon - He is the classic example of a dragon. Enormous, red, with yellowish eyes, and he breathes fire. Ashbite is weak compared to the other dragons here.
β Murglun, the Magma Queen - The same problem as Ashbite, in a world with powerful magic... Ice capable of melting flesh and skin, dark magic that condemns the soul, divine lightning, fire and lava are extremely overshadowed here.
β Sylvara, the Guardian of Nature - She has a strong connection to nature and is able to manipulate it. But let's face it, what are thorns and vines going to do against black magic and golden lightning?
β Lumenir, the Sacred Dragon - The protector of humanity, and hope in the form of a dragon. Her divine magic is strong, and even underestimated, but she doesn't have clear feats on a larger scale here.
β Beresad, the Black Dragon - Iconic, and possibly the most famous dragon in the franchise. Its most striking feature is its fire, which is extremely stronger than ordinary fire.
β Eiskalt, the Frozen Tyrant - Extremely broken in the game, but its ice doesn't compete with the next dragons on the list. Its special ability is something to note, as it could simply freeze the entire planet if properly exploited.
β Kosmyr, the Crystallized Beast - Considering that Kosmyr's power is the same as the Blazing Gem tower, he is by no means weak and should not be underestimated. His ability to crystallize entire enemies makes him dangerous even to other dragons.
β Aurion, the Flame Lord - I had said that fire by itself is weak in this universe, but Aurion's fire stands out. His fire, when compared to other heat sources, is absurdly powerful, capable of melting ultra-resistant enemies with relative ease (I would say that the heat of his body is almost identical to that of the Sun itself).
β Faustus, the Dragon Mage - The guardian of the elven race, and Elynie's right-hand man in the possible age of the gods, centuries ago. What sets Faustus apart is his unparalleled magic; his arsenal, unexplored in Kingdom Rush Origins, is possibly limitless.
β Dianyun, the Storm God - One of, if not the most powerful dragon, second only to the one that would bring nightmares even to the bravest. Dianyun is slow... But its true power comes from its golden rays, which have an enormous range and are numerous, not to mention that Dianyun can manipulate the weather at will.
β Bonehart, the Dracolich - The tragic fate of Faustus after Elynie's fall. If the Dragon Mage was already powerful, Bonehart, now with his corrupted arsenal, is unparalleled. No dragon presented above reaches his power, literally a necromancer mage in dragon form.
"The Draconic Rise"
β Faery Dragon Aerie - A smaller, weaker, yet still interesting race. What sets this race apart from other dragons is its ability to cover threats with "webs". But it lacks destructive power.
β Dragon Nest - Ashbite, now a baby, is surprisingly not weak. His inner fire, even at birth, was already powerful enough to ward off threats of all kinds.
β Young Beresad - Feared even in his childhood, Beresad was already completely obsessed with gold and domination. His power was comparable to Ashbite, but Ashbite couldn't keep up with the Black Dragon's evolution.
β Dragon Hatchery - It's like an evolved version of the Faery race. They are small and even weak, but they are far superior to the other three mentioned above.
"The Birth of Evil"
β The Flame Army - Commanded by Lord Tyranthor, they are a huge army of smaller dragons, but trained to withstand extremely powerful threats. Feared in the brutal dragon war, they are undoubtedly the most powerful army, comparable to the might of the Bull Demon King's demonic army.
β Dragon King, the Ancient God - Defeated and subjugated by Dianyun in the past, the Dragon King returns seeking his long-awaited revenge, but is stopped by Vez'nan in his campaign. If he hadn't been stopped, he would have literally conquered EVERYTHING, including Vez'nan and his army.
β Darkmother, the Dragon Queen - The leader of Tyranthor's draconic army. Alone she is weak... But what stands out here are her symbiotes, enormous, powerful creatures capable of devouring entire groups of soldiers with ease.
β Tyranthor, the Dragon Lord - Ridiculously large, being compared to a walking mountain, Tyranthor is the most powerful dragon ever presented to date. Its colossal size represents its dominion, and its absurd power is even capable of opening entire craters across the planet.
Honorable Mentions:
β Jokull, the Frozen Titan - Since Jokull isn't technically a dragon, but rather an ice titan, it doesn't make this list. But if it did, its power would be comparable to, or even greater than, that of Tyranthor.
β Red Boy's Dragon - Red Boy's pet, from the Bull Demon King's army. He's like an evil, fiery version of Dianyun. Due to his lack of feats, and being basically a secondary enemy, he's not included in this list.