Akutoku Kizoku no Seizon Senryaku

While playing games after my wife betrayed me, I suddenly died and woke up as Jack Girard, the protagonist of the fangame Survival Strategies of a Corrupt Aristocrat. Unfortunately, Jack has it even worse than I do. Between his parents trying to assassinate him, the betrayal of his personal maid and the house's butler, and a host of other horrors, his life—now my life—is one treacherous twist after another. However, with the help of Adele, the strongest supporting character of the game, and my foreknowledge of said twists, I'm determined to overcome it all and live in the lap of luxury!

(Source: J-Novel Club)