...my oldest son and I noticed how closely the ending paralleled the climax of "how to save your dragon 2"

e.g.

new "alpha" comes in and takes away the trusted pack from the hero

trusted pack overcomes its programming/instincts and returns to the original "alpha"

the villian, who didn't respect the animal and only wanted to use them as weapons, gets their come-uppance by said disrepsected animals