Get 19 rexes with 40k health and 600 melee with mastercraft saddles. They will be used as crowd control for the dimorphs and teras. You will need a male deer with 10k health and a journeyman+ saddle. Get the deer under he dragon when it lands so it gets stuck. Have shotguns with 180+ damage to them shoot the dragon. And also, make sure you have journeyman+ tiered flak to bring in too!! 2-3 sets of armor recommended
If your planing to tame this thing don’t. Even if you force tame it it soon disappears. I suggest just getting a mod to get one. Get a mod, firce tame the mod dragons and, BOOM. Your own OP dragon. So don’t waste your time spawning in the boss dragon and taming it. Just get a mod.