MidGard
I actually think that some of felix's quip might doom him to be found out though. Remember the time he buy potions and said "the term when you go black you never go back, in the place where i come from, you would not have said that" I feel like felix might sometime accidentally show his cultural hints. Of course i really doubt princess bird know about his dealings with the blackmarket guy, but who knows, one day the differences in culture and him messing up might be the only way people can figure out his identity
Felix has been very careful to ONLY show abilities in one persona or another. The simple fact "Landlord" showed up in Games over a year before anyone else from Earth had their act together should make it hard to pin him down. Especially because Landlord clearly has a ton of practice and Earth got access to VR at a specific date that is easy to find.
Random thought here. Why is Felix buying high-tier bloodline "lotteries" and re-selling at a loss? When he COULD be buying hundreds or thousands of low tier and "mixed" bottles on the open market and reselling the purified bottles at a profit now that he has a sales outlet? I mean that first bottle he got had THREE bloodlines in it! Keep the primagenter ones for himself and sell others by the bottle. Any time he filters out a rare/legendary bloodline from low-tier bottles he's made an epic profit!
Felix has never shown himself publicly in a supremacy game, the Earth games have not even started yet. I dont think Earth is even on these guys' radar so I almost positive Felix is fine. Princess Bird must have found people similiar to him. What Felix needs to do is get another element and bloodline quick so he can give it to his persona on Earth. Hopefully this will make it less likely for people to realize that Felix and Landlord are the same person because they only share 1 element, poison.