In the history of this war, the Emperor created a total of 20 Legions, meaning there were 21 Primarchs. The protagonist is the 20th Primarch. [The protagonist is a transmigrator, but due to the Primarch's long lifespan, he has forgotten his original memories. Compared to his original memories, his memories as a Primarch are much richer, causing him to forget his past life, though he still retains some recollection.] (The history of Warhammer won't change much; Horus will still rebel, and Sangeles will still die.) The protagonist, raised by a member of the Mechanicus clique, possesses advanced technology, but given his personality, he won't create any machines.