Isaac is the best friend of Augustus Waters, and is also a cancer patient. At the beginning of the story, Isaac-a cancer patient who already had to have one eye removed- goes to the Cancer Support Group that Hazel does to. When he finds out that his second eye will have to be removed, he brings his best friend Augustus Waters to support group as well. And that s where Augustus and Hazel meet for the first time. Isaac started out in the book dating a girl named Monica, and they would constantly say the word, "Always" back and forth which represented that their love would last forever and always be there. (Augustus and Hazel later come up with their own version of "Always" and say "Okay" back and forth to represent their love for each other.) Monica later broke up with Isaac because she could not handle Isaac loosing his eyesight. Throughout the book, Isaac struggles to accept why Monica broke up with him if she was "always" in love with him. He goes from being a cancer ridden guy, insanely in love with is girlfriend, to a single, brokenhearted, blind teenager whose best friend has died from the beginning to the end of this book. Thats why Isaac is a dynamic character, although he isn't all that much of a particularly round character.