This intial offering of 4 Deluxe Legion Builders was available during a private crowdfunding campaign for the Mythic Legions Tactics: War of the Aetherblade game that ran in Jan/Feb 2021. Those figures came with extra "bonus" heads, as well as "Forge Founder" designations on the packages showing they were from that initial run.
The follow-up public campaign on Kickstarter, which ran from July 29 - Sept 1, 2021, included these 4 same builde sets (minus the bonus heads), plus a new 2-pack set featuring updated versions of Gorgo Aetherblade and Attila Leossyr.