Firstly the Titan Dragon is red rather than blue, and I believe is slightly larger.
The dragon can collect significantly more Fish and Wood as a Titan, level 52 collects over twice the amount level 51 does.
Finally you have to feed a Titan Dragon 4 times to increase it to the next level rather than 3.
Those are the main differences, there might be some more when battle mode comes out.
does their ability of fire enchance and hidden secert ability like maybe spines grow longer and possible fire jacket shown to grow larger that monstrous nightmare reales hidden ability of fire wing cutter attack like realse fire attacks from flapping wings of cutter on it emenys
Sorry, all of that is beyond me I'm afraid, I only know about Titans in the Rise of Berk game, I don't know if they appear anywhere else in the franchise or even if they have information like the size of them in feet.