You do not want to pump health on your Rex’s or theirs you want all melee Bc the dragons fire does percentage damage to your Dino’s and carnivores take more percentage and herbivores take less percentage damage from the fire breath so you wanna use theirs and veggie cakes are helpful with a Yuty and you should be fine and saddles don’t matter a ton but they will help from the other Dino’s and his bite attack and fireball and the fireball can kill you off your mount so run around with you Dino’s in follow and when the dragon lands whistle it and buff then when it flys off whistle follow again and repeat

So if this is your first time fighting this guy I have a few tips. One thing is herbivores preferably therizinosaurs they are the best in my experience any way. Herbivores take less fire damage. You need a decent set of ghillie. BRING HEALTH POTIONS!!! The pteranodons and dimorphidons will do damage to you and so will the fireball. Do your best not to get hit, always stay moving. Take a cillia brew or whatever it’s called it will help and canteens. Hope this helped!

Recently took on this creature again in Ark Survival Evolved and I have a few tips that could be helpful for your victory:

1. Creatures you'll need 1 Yutyrannus and 19 Therizino's

2. Recommended stats for the Yuty 50k health and 3 - 3.5k Stamina having it imprinted as a baby also helps. Reason for this there is a chance where you might get hit by a fireball or set on fire by the Dragons breath attack so better to be safe with a little extra health.

3. Recommended Stats for the Therizino's 35k health and 1.1k melee (side note these are what I was able to get from breeding good stats and no mutations and only primitive saddles I couldn't find any blueprints for better ones) Therizino's are the best for taking on the dragon as it does More damage to Carnivores than Herbivores

4. Gear you will need to take on with you:

A. Full Ghille suit it's hot in the arena so having good pieces of Ghille for the heat and armor protection will be crucial as Dimorphodon spawn in the arena and will be able to hit you even if you are on a mount so high armor and high durability on that armor

B. Medical Brews you will take damage in this fight there is no avoiding it better to heal up as soon as possible with these obviously you'll also have food and water on you no need to die to not having these things

C. Pump Shotgun this is a must you won't be out of this fight best to get as much damage in as possible. I was using a Journeyman one that I got from a blueprint that had a damage of 180 it's all I could find if you find a better one then you are in good shape. I was carrying abou 3-4 stacks of ammo.

5. Veggie Cakes I didn't use Veggie Cakes during the Gamma or Beta Fights you can if you want to but I didn't need to use them. Alpha however I would recommend having them I gave my Therizino's 16 Veggie Cakes. I recommend getting yourself a beehive or 2 to help this process.

So this is how the fight will go as soon as you spawn in hop onto your Yuty walk away from your tames then hop off and shotgun the dragon once to get it's agro while it's in the air the dragon will start shooting fireballs at you so be sure to dodge them the less damage your tames take the better. Pteranadon and Dimorphodon will spawn in and agro onto you so if you have to run to your tames so they can kill them for you, do this in between fireball attacks after they're delt with keep dodging fireball attacks until the dragon lands. Do not cross the lava river there is no need to do that the dragon will cross the river and come towards you. Your tames will take unnecessary damage and some of them will get stuck. Once it's across the river whistle attack onto it and courage roar with the Yuty to boost them up. Make sure your Yuty is on Passive when you do all this you don't want it to run straight at the dragon and get killed, and stand back far enough so you don't get set on fire during its breath attack. Once you dismount use your Pump Shotgun to get in that extra damage as much as you can just be sure to watch out for the Dimorphodons and Pteranadons. If it flies away just whistle your Therizino's back into the corner and do the same thing as before with drawing agro and avoiding fireballs. Other than that if you succeed congratulations you defeated one of the hardest bosses before your fight with the Overseer. I did this in single player solo on difficulty 5 had to override the game files so that dinos up to level 150 could spawn. If you found this helpful please feel free to subscribe to me on YouTube at SpiritPlayzGames I plan to start doing Ark content in the future as I absolutely love this game!