About the Time I Traveled to the Warhammer World

What will happen when a mortal travels to one of the forbidden areas of the traveler? Will the suddenly extra 21 Primarchs and the unknown 21 Legions attack the evil god during the Horus Heresy? Or always believe in the Emperor and stick to your post until the last moment. Everything has to start from the beginning. I found that I still can't write an introduction well. Sometimes I don't write well. Please forgive me. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.