If you want to find a royal griffin, look at the map and look at the green obelisk ( in other words the green tower) then go there look at map again and find a mountain up north, the mountain is near the carno island. Careful, because there will be gigas that can spawn to the mountain near carno island
The easier way is go top right and go to carno island but stop to the mountain that's is near the island, go near the mountain, if you find an unusual argy with four leggs and the name is not griffin or argy, then its definitely a royal griffin,
Tge names are like a players name, you can only tame them with the same surname ( about three the same letters in the ending bit) or you can tame them over level 85.
If you want the kibble, tame 4 or 5 griffins with all common surnames because they won’t mate outside their royal family! Then, you’ll be getting a steady amount of kibble every now and then 👍 I have 5 very low level griffs just for kibble and I basically get 3 Griffin kibble about every 15 hours.