I havent been able to find a lot of content about lore of the Warforged being created and was thinking of running a 5e campaign taking place during the Last War of Eberron, with the Day of Mourning being an event during the campaign. Eventually the war ending in the Treaty of Thronehold. Before I start really building the campaign spanning several years, I would like some information on warforged specifically: I know Warforged were invented during this time period, but can they become Undead?

As a further follow up, is there any content on how a Warforged is created? I've got the Wayfinders Guide to Eberron book, but was wondering if theres any material to help with the world building in any edition or anything on warforged specifically. Hope someone can help me out with this!

I was told to come here from r/dndnext and told you guys can hopefully help me out with this, many thanks!

Edit: some timeline fixes because I had some dates wrong for events