Porphyrion

Porphyrion was even taller, and even more ripped. He didn’t radiate heat, or show any signs of breathing fire, but there was something more terrible about him—a kind of strength, even magnetism, as if the giant were so huge and dense he had his own gravitational field.
Like Enceladus, the giant king was humanoid from the waist up, clad in bronze armor, and from the waist down he had scaly dragon’s legs; but his skin was the color of lima beans. His hair was green as summer leaves, braided in long locks and decorated with weapons—daggers, axes, and full-size swords, some of them bent and bloody—maybe trophies taken from demigods eons before. When the giant opened his eyes, they were blank white, like polished marble. He took a deep breath.
“Alive!” he bellowed. “Praise to Gaea!”
Jason made a heroic little whimpering sound he hoped his friends couldn’t hear. He was very sure no demigod could solo this guy. Porphyrion could lift mountains. He could crush Jason with one finger.

Jason stepped forward and yelled to get back Porphyrion’s attention.
“You said a demigod killed you,” he shouted. “How, if we’re so puny?”
“Hal! You think | would explain it to you? | was created to be Zeus’s replacement, born to destroy the lord of the sky. | shall take his throne. | shall take his wife—or, if she will not have me, | will let the earth consume her life force. What you see before you, child, is only my weakened form. | will grow stronger by the hour, until | am invincible. But | am already quite capable of smashing you to a grease spot!”
He rose to his full height and held out his hand. A twenty-foot spear shot from the earth. He grasped it, then stomped the ground with his dragon’s feet. The ruins shook. The idea of fighting a forty-foot-tall immortal bare handed was so ridiculous, even the giant seemed surprised.

Forty feet away, Percy bent over the giant king, trying to yank a sword from the braids of his hair. But Porphyrion wasn’t as stunned as he let on.
‘Fools!’ Porphyrion backhanded Percy like a pesky fly. The son of Poseidon flew into a column with a sickening crunch.
Porphyrion rose. ‘These demigods cannot kill us! They do not have the help of the gods. Remember who you are!’
The giants closed in. A dozen spears were pointed at Piper’s chest.
Annabeth struggled to her feet. She retrieved Periboia’s hunting knife, but she could barely stand upright, much less fight. Each time a drop of her blood hit the ground it bubbled, turning from red to gold.
Percy tried to stand, but he was obviously dazed.

TLH ch.50 and BoO ch.43