Enceladus

Enceladus is one of the giants.

Physical Appearance
Enceladus is 30-foot (plus) tall giant, which is apparently smaller than most other giants as well as the weakest. From the top he is a humanoid with bronze armour decorated with a flame design. He has dreadlocks and his eyes are marble white. From the bottom his dragon legs are green and and he has claws as feet. His weapon is a spear about the size of a flag pole.

Ancient Mythology
Enceladus joined the Giants in the attack on Mount Olympus. He was created to destroy Athena. He was slain by a spear thrown by Athena and an arrow from Hercules bow at the exact same time centuries ago.

Powers
Enceladus is capable of breathing fire, like a dragon.

The Lost Hero
In The Lost Hero, he claims he was born to fight Athena. Called "Anti-Athena". He was killed at Mt. Diablo by Jason Grace and a lighting bolt from Zeus(as the combined force of the gods and demigods) in "The Lost Hero."

Other Info
His allies are the Earthborn and Gaea/Gaia. In the series, he was banished to Tartarus. Jason and Zeus killed him the second time by summoning lightning.

He is (or so he claims) smarter then all the other giants due to the fact that he was created to kill Athena.