I agree with this point. The CEO does just what he was told to. I assume he's just an employee without ownership, and employees don't fire owners unless someone much stronger is behind them.

Definitely lawyer up, that would be a first thing. Then, if you want to regain control about he company, consider CEO your enemy, not the CTO. Invent a reason and fire the CTO, if you can do it. Then, step up as CTO yourself, or at least hire a person you trust. Then, hire COO, CFO, CMO. Make sure those are people that are loyal to you and where each one will take over one of the CEO responsibilities. At the latest stage, let those people document every mistake of CEO, and you try to push him out together with C team and investors.

That's exactly what he is doing to you. He convinced you to voluntarily step out from CTO position and hired his tool. Now, your chances to fight back are much worse from this position, but the war is not yet over.

So, lawyer up, read Machiavelli, know your enemy and fight fire with fire. Remember, the CEO that did this to you is not your friend anymore, and deserves whatever you do to him.

Personally, i consider this bad advice. Fighting is never really a good thing. SO please don't start a civil war, all it will do is destroy the company. The whole vengeance thing is very counter productive. I'd say lawyer up to get compensation and not to take revenge. And then leave and find a place where you are more appreciated. perhaps focus your energies on something new , something productive

It depends. Is company worth fighting for? What would be your share if you keep your part of the slice? If that is bigger than compensation you would get, than it certainly is worth fighting for. It's not about vengeance, it's about founders own interests, even if that would make company worse off.

45% share of 100M$ worth company is still much more than 10% share of 200M$ worth company or 1M$ compensation. You are not fighting to optimize for the company success, you are fighting to optimize your own wealth. If the company gets destroyed, and you still manage to get more then what would be your compensation package, you are still better off then retreating. Why caring about the company that doesn't benefit you, you would certainly not enjoy the success of the company that squeezed you out.

So yes, lawyer up and fight if it's worth to you to fight for the control. Don't be emotional about he company and business. It's your weakness, and they are already playing on that.

Well as someone here pointed out, the whole fighting thing is toxic. It even marks YOU for the rest of your career. You can't just go to everyone and say "he started it!". outsiders would see BOTH of you as dangerous, and would likely avoid working with you. So it's more of a suicide mission really