This is the illustrated version of Xyz.

Napoleon Xylophone Book 2.
This story has a different kind of hero; a hero with a walking disability. Xyz is the standalone second book in Frank Lambert's Napoleon Xylophone trilogy, named after his first novel. Isaac Bonnyman doesn't realise that the rogue changeling he is hunting for the Cult of the Clan will lead him to the secret to immortality. It is not until he is dead that he realises that's why the Clan employed him. Once he is dead, he doesn't care about the Clan or changelings; all he cares about is feeding on live prey. Zam doesn't want to ask Bonnyman for help, but having a doppelganger and a wraith chasing him down means he has little choice but to search for Bonnyman in the City of the Dead beneath Edinburgh. He travels to Scotland with two ghosts following him in his high-tech wheelchair that can morph into an exoskeleton one minute and a flying machine the next. When he eventually finds Bonnyman, who agrees to help Zam, they both learn a valuable lesson. One learns that it is possible to undo death if you betray a friend, while the other learns that even after death, friendships can be formed that will last forever... Xyz is an inspirational fantasy novel that will appeal to young adults.