I think that it's just regular level 3 armor from Lt training, add in sacred tortoise to make it level 5. Yes the Lt training will give you level 3 armor for BOTH you and the Lt itself, but the sacred tortoise will only affect you, giving you level 5 armor. Once you're in level 5 armor already, the only way you can be knocked off the mount is if they manage to knock up your mount (which still only have level 3 armor). But elephant mount can't be knocked up. So whoever is only top of the mount is essentially invincible since they're too high to be hit, and the only way you can knock them off now is by killing the elephant, which would be hard to kill.
The real upgrade here is probably the earthquake charge attack it have, which apparently, can't be flipped out of, which would be pretty dangerous.
Main:
ZhiFang.NA1Wiki name: ZFlavender.Currently favorite weapon: Twin Maces.