Jack Vranes would best be described as loyal and fearless. Originally a bully to Michael he quickly becomes one of Michael's close friends after being recruited into the Electroclan along with his best friend, Wade West. His girlfriend is Abi, one of the members of the Electroclan and a Glow.
Jack has a tall, muscular, and burly physique, which is no wonder after he does several exercise workouts each day. Michael noted in The Final Spark that his biceps were the size of a buff person's thighs, and Jack often went on a insect and raw egg diet.
Jack is very loyal and has adopted the soldier mindset as his brother. Never leave anyone behind and give a 110%. As compared to Wade, Jack is definitely the brawn behind the group while Wade is more likely to stay back and think about their situation. He is as brave as Michael and willing to give his life to help someone.
Jack started out as a bully to Michael Vey and his friend Ostin. Michael asked Jack to take him Pasadena, California and the two become friends as the rescue mission goes on.