Nicknamed the Dragon of the West, Iroh is a retired general and considered a great hero to the Fire Nation. He is the brother of Fire Lord Ozai, making him Prince Zuko's uncle. While he was still active in the war, he and his army laid siege to the great Earth Kingdom city Ba Sing Se. For 600 days they battled, but when his beloved son Lu Ten died in battle, he was devastated and abandoned the siege.
Iroh is wise, laid-back, clever, enjoys drinking tea, and is not to be underestimated. He may be getting on in his years but he is very strong, a powerful firebender, and always has an ace up his sleeve. He has an amazing balance between being serious and playful, and always knows when to be what.
Because Iroh was the oldest son of Fire Lord Azulon, he was suppose to become the next Fire Lord. But due to his personal tragedy at Ba Sing Se and his brother's thirst for power, a royal conspiracy was had while Iroh was still away, and the crown was given to Ozai when Azulon died.
When Prince Zuko was banished and went to sea to search for the Avatar two years ago, Iroh went with him. He personally trained Zuko in the way of Firebending, and didn't abandon him when the rest of the family and nation did. Iroh, with his patience and wisdom, balances out Zuko's impatience and short-tempered attitude, which is good considering how often Zuko's rage gets them into trouble. Tea is his drink of choice, his favorite being Ginseng. He is also a master bargain hunter, and truly cares for Zuko's wellbeing.