Boros

Boros was a towering, one-eyed alien whose spiky pink hair fell in bangs across his face. Rows of gold rings lined his pointed ears, sharp teeth filled his mouth, and his single large eye sat above pale blue skin veined with dark, crack-like markings that spread from the eye across much of his body. He wore spiked armor at the shoulders and forearms over curved boots, white harem trousers, and a magenta sash hung with bladed weapons, with a red orb set on his chest.

Once Saitama destroyed that armor, Boros surged into a second form: bulkier muscle, jutting plates, an exposed spine, deep navy skin lit by glowing blue lines, and a second yellow eye opening beneath his chest. His ultimate Meteoric Burst state changed him yet again, his hair lengthening down his back, his eye whitening, and his whole body wrapped in white energy.

Immense power made Boros both haughty and proud. A genuine love of combat, paired with his failure to find any equal, sent him drifting across space in search of a real challenge. He was largely indifferent to the carnage he caused, unmoved by A-City's ruin or by the deaths of most of his crew, yet he could still show flashes of courtesy, reassuring a worried Geryuganshoop and greeting Saitama with warmth.

The longer Saitama withstood his assault, the more Boros came to respect him, and once beaten he met his approaching death calmly, fulfilled by the exhilarating fight regardless of the outcome. In battle itself he was careful and serious, preferring to end matters quickly and deny his opponent any chance to surprise him.

As commander of the alien invasion, Boros held absolute authority over his armada and possessed staggering power. His people, he claimed, had evolved the universe's finest regeneration to survive their harsh homeworld, and he insisted his own regeneration, strength, and latent energy dwarfed the rest of his race. Famously, he became the first foe shown to survive a punch from Saitama, losing only his restraining armor to that first blow. The armor existed solely to cap his true might; freed of it, he fought on through a string of normal punches, a Consecutive Normal Punches barrage, and finally the shockwave of a Serious Punch.

His strength let him hurl Saitama through the pillars of his own ship and burst through its durable outer hull, while energy blasts fired from the eye in his chest scorched the vessel and leveled city-sized swaths of ground. Torn apart, he simply regenerated, regrowing a lost arm in an instant, until his energy finally ran dry. His trump card, Meteoric Burst, flooded his body with latent energy to push his speed and power past their limits at the cost of his own lifespan; while active it let him kick Saitama clear to the Moon and culminated in the Collapsing Star Roaring Cannon, a mouth-fired beam he swore could scorch the Earth's surface. It was against this final attack that Saitama's Serious Punch broke through, leaving Boros too spent to recover. Though he died, he did so praising the battle, admitting the prophesied match had proven far stronger than any seer had promised.