After Traveling to Demon Slayer, I Became a Cannon Pillar

"That Hashira-sama's Nichirin Sword is different!" The members of the Demon Slayer Squad said so. The dark and cold appearance, the hollow texture, as if the flaming death reaping life will appear from it at any moment! She is the girl named "Cannon Pillar" Jealous of his younger brother's talent, he thought he would be able to overcome his inner demons after becoming a ghost. Unexpectedly, he met a girl who fell from the sky. "Sir! Times have changed!" The girl who was raised by Hei Death Mo was carrying Gatling, who was burning with blue fire, and pointed at Hei Death Mo's face. There may be various ridiculous plots, various Mary Sues, and invincible settings... If you mind, please avoid it. Purpose: love and justice