So Mc joins a "competition" where they car receive "Legacies" or "Inheritance" and then he does whatever a Mc has to do....and then he fiends an egg, waits for the egg to hatch.........*fast forward to another scene* He, the cat and a girl are transported to another place, where he and cat trick a girl into protecting them.....thats all i remember.
Haven't read it in a long time so I'm not sure but is this what your looking for? The Spearmaster and the Black Cat