: Most valuable resources, including Gems , are stored on Konami's servers. Cheat Engine only modifies local memory; if you try to change your Gem count, it will likely be a "visual-only" change that disappears when you try to spend them or refresh the game.
Yu-Gi-Oh! Master Duel , however, is an always-online client-server architecture game. Yu-Gi-Oh- Master Duel - FearLess Cheat Engine
As of the latest update (Version 1.5+),