Origins[]
The Titan is a colossal humanoid whose origins lie specifically within Greek Mythology. The most famous account of their existence stems from the Titanomachy (the Titan War against the Olympian gods). Likewise, most other myths about the Titans stem into or branch from accounts of the Titanomachy.
These include the sky-god Zeus deposing his father, Kronos, the Titan god of time, after an attempt on his life and the life of his brothers and sisters (Poseidon, Hades, Hera, Demeter and Hestia) when they were still only youngsters; and Atlas, the Titan god of daring and endurance, being set to bear the firmament (the dome of the sky) on his shoulders as punishment for actually INCITING the other Titans to rebel against Zeus.
Appearance[]
A Titan is, to a giant, what a giant is to a human. They are enormous, gargantuan, brobdingnagian, massive, colossal, gigantic, mammoth, huge, large and any other word you may use to say 'BIG'. They are easily the size of mountains, making them among the largest sentient beings in existence (THE largest, if one does not count extradimensional entities and various constructs...).
However, otherwise, their looks are basically humanoid. The males may be brutish and unkempt sometimes, but a handsome Titan is not unknown (Helios, the Titan god of the Sun, in fact, was said to be literally radiant as far as physical beauty). Likewise, the females are beautiful, almost always looking strong and healthy (though, again, a dainty, demure Titaness is not unheard of; Theia, Titan goddess of heavenly light, Leto, Titan goddess of motherhood and womanly demure; the list goes on).
Behavior[]
Titans vary in personality and behavior as many other humanoids do. Some are gruff slobs with no manners. Others are mean and domineering, total bullies. However, others are prudent, wise and philosophical; still others are even shy and bashful, gentle giants. There is no cookie-cutter description of a Titan.
And yet, despite this, one thing IS for certain, should one cross the path of a Titan or a Titanis; they fear none, they bow to none, and only the gods themselves oppose them.
Abilities[]
The abilities of the Titans, naturally, stem from their divine lineage. This means that, due mainly to their colossal stature, they innately possess Superhuman Strength, Durability, Endurance and Toughness; physical impacts, magic, poisons, acid, diseases/sicknesses/illnesses, radiation, sonic attacks and the like do precious little to bring them harm. Furthermore, they are gifted with an alarmingly fast healing factor, and surprising longevity (even perhaps on par with that of an angel's).
Besides those capabilities, some may have physical powers, some mental powers, but whatever abilities they possess depends on the domain to which they are attuned. This often affords them great psychic insights or the ability to wield the raw, elemental forces of nature for weapons.
Overall, these beings are not to be trifled with. Whether they preside over some element of nature so base as animal life, or rule over one of the more potent elements like fire, water, earth or wind--or even dominate some fundamental force like time or intellect or mortality--their raw power far exceeds mortal comprehension...and competition.