I was gonna suggest Tezcatlipoca since that what I named my Defensive Landorus-TSo as you may know Landorus origin comes from many different mythological sources like genies and the chinese white tiger and the Jaguar gods of Aztec mythology. I am Mexican so I know some thing of Mesoamerican mythology. First the Aztec deity Tezcatlipoca its name actually means "Smoking Mirror" which kinda matches with the whole Reveal Glass item ingame which reveals the Genies' true form. This deity is related to the sky and to the earth and it had two forms Humanoid and Jaguar just like Landorus. Even though this matches so well with the concept of landorus this deity was kinda evil and liked to cause conflicts in order to bring change to the world, according to the lore. Plus the name isn't that cool.
There's another mythical being this time from Mayan culture that matches another aspect of Landorus. The Balam specifically the Balam Kol/Col This where Jaguar Genies that protected the lands and crops. Mayans prayed to them before sowing so they can get blessed with a good harvest.
They are described as ugly bearded old men with an Intimidating look. They use sharp obsidian projectiles(Stone Edge) to defend the crops from evil spirits, animals or humans. I like to relate Landorus to this mythological being better as it matches with "The Guardian of the Fields" title Landous has and it also is related to a big cat, lol this deity even uses Stone Miss like most Landorus do :P
So yeah sorry for the long post my suggestion is Balam Kol :)
Yes.Name it, "Kaiser"
Edit: Damn! Too late?!