Armory System: In the Tang Dynasty, I'm Taiping's Cousin

[Not an alternate history + Tang Dynasty + System + War + Technological Overkill + Invincible + One-Man Army + Thrilling + Ascension to the Throne + Multiple Heroines] Elite soldier Li Yixun transmigrates to the Tang Dynasty and obtains the [Arsenal System]. <All firearms are bound to and recognize their Host. No one else can use them.> “Damn! The price is way too high, even if it was to protect me!” Fortunately, the arsenal has everything, including nuclear weapons! Li Yixun uses a sniper rifle for long-range attacks and a shotgun up close. He puts on a bulletproof vest, and if that won't do, he brings out an armored car, a tank, or missiles. He's afraid of no one! “One man can conquer the realm, but he can't hold it alone. I need to enter the tiger's den and use strategy...” [Reader's Guide]: Taking another's place; husband of Princess Taiping; sniping Li Longji; mowing down the imperial guards with machine guns; blasting the rebels with cannons; bombing Tubo with missiles; attacking Goguryeo with fighter jets; dropping nuclear bombs...