OOC: Your speaking about the most present charge? Then answer is shortly; nop. You do not get to do readied action nor any AoO as you did not see him until he hitted you with his sword. But considering your readied action was 'hit the guy if he appears inside my reach' so you can do your readied action after the results of his attacks are solved out first. But it can become invalid action if you get bull rushed beyond reach of your tentacles (you need do resist roll vs bull rush which had 98 check and each point failed pushes you 5'ft away from him in half-horizontal angle which makes you go through your own tornado and then hit onto ocean).