Obliteration
This Epic is like a god of destruction. He enjoys exploding buildings, a symbol for his tendency to destroy communities. He is a force of nature akin to the Greek Titans. His nature is fully revealed when he attacks David and submerges him under water. This shows him as an agent that takes order and makes it into chaos. He takes buildings and explodes them, sending their debris into the water below. He is like a Japanese Kaiju, a destroyer of urban epicenters.
The Prof
David is helped and guided by a super-intelligent man whose name (Phaedrus) is borrowed from an important work by the famous philosopher Plato. His "formal" knowledge helps David to navigate a complicated world that to be honest, he doesn't always understand. The Prof represents guidance and potential. When he removes himself from community to keep his powers from harming anyone it is shown that David's own potential is wildly powerful and capable of great disruption.
David and water
David is nearly killed by Obliteration when an attack sends him underwater where he thinks he will drown. He is saved by the team, and instead of water destroying him and killing him, David is resurrected from his water tomb and given power over water. He is given a gun that shoots water which helps him in his battle against the star Epic, Calamity. This makes David into a nearly Biblical hero, risen from the dead, given power over the chaotic element of death (water), and powerful over the Epic evil forces.
Megan as a symbol
Megan is also a symbol for David's journey. Although she is a character, she symbolizes parts of David that David doesn't understand. She is connected to magical powers, and with her magic, she summons reality from alternate timelines. That shows David's potential to change fate. Why is David's character symbolized in the girl that he loves? Because he admires about her the things he wishes he had in himself; when she dies for the team, that is a symbol that David must have her inside him to carry on. If not, then how will the team go on to fight without her important contribution? She represents what he can accomplish with love as his motivation.
The allegory of teamwork
The book can be seen as an elaborate allegory pointing to the importance of teamwork. The allegorical component is clear from the archetypal shape of the characters (The Prof is like a wise old man; the dangerous, death-threatening love interest is the femme fatale). Also, the allegory is clear because the literally "Epic" enemies are so powerful that without cooperation, the team will fail. In order to succeed, they have to use each other's skills in a constructive, cooperative way, without letting conflict ruin them.
