Nuclear-powered Sword Immortal

By the coast, a hundred-meter Star Gate shimmered with flowing light.
Beyond the Star Gate, an army forged of steel stretched as far as the eye could see.
Above the Sky Dome, squadrons of fighter jets streaked across, weaving an iron curtain.
In the distant ocean, scores of aircraft carriers, destroyers, and frigates dotted the seascape, ready for action.
All cannons were aimed at the figure who emerged from the Star Gate.
"In the name of the Federation Command Center, I order you to stand down, or what awaits you is total war," said the voice.
"War?"

Gu Jinlai took a step forward, and his form swelled against the wind, in an instant growing from less than two meters tall to a colossal Chaos Demon God thousands of kilometers high, emitting the brilliance of a white dwarf star from his being, his own gravity causing thunder and lightning, as well as tsunamis and tides within a thousand-mile radius.
He looked down...
At the war weapons that seemed like toys.
He reached out, and a hydrogen bomb fell into his hand.

Within him, the electron-degenerate star core released Helium, Helium elements expanded, and the terrifying high temperature instantly caused Deuterium and Tritium, Hydrogen's isotopes, to fuse, the energy bursting forth, forming a blazing white brilliance on the ocean's surface that was like igniting a sun.
Before this sun's energy could be released, he clapped his hands together, and the dazzling white, mixed with heat in the billions of degrees, was compressed and sealed within his palms, not a fragment escaping.

"I think, you should choose peace." he suggested.