Modern unlockers for Shogun 2 typically use a "Proxy" method:
The original Steam API file ( steam_api.dll ) is renamed (e.g., to steam_api_o.dll ).
: These tools act as a "middleman" between the game and Steam. When the game asks Steam, "Does this user own the Sengoku Jidai Unit Pack ?", the wrapper intercepts the request and sends back a "Yes".
: Unlike API wrappers, these are standard game mods (often found on the Total War Center ) that edit the game’s internal database to make minor, unplayable factions available for selection in the campaign. How They Work