This can go one of two ways. 1) Let's be optimistic: this new CTO is an amazing person, super smart, will bring a lot of value to the company, and you will gro

This can go one of two ways. 1) Let's be optimistic: this new CTO is an amazing person, super smart, will bring a lot of value to the company, and you will grow a lot by working with that person. So it's good. 2) The pessimistic view: this move was purely political, this new CTO is no one special, it's just one extra layer of management and taking your responsibilities away. You were doing a great job before, and now your job is made more complicated and less efficient. Swallow your ego for a second and give that person a chance. If they perform really well, then admit it was the right move. If they are just average, then think of your next step. It doesn't mean quitting necessarily. It could just be that after a few months, it becomes clear that the CTO is not that great and your influence may be restored. Or maybe it's an opportunity for you to offload some of your current tasks and take on new parts of the company (get more involved in sales, or whatever else you are curious about).