Even before the battle started, the innate intimidation effects of absolute power which was the main trait of the ruling Crocodile kingdom was nullified.
Sebastian's plan was not anything complicated. It was mainly focused on getting an early advantage for the Draconic Lizard family and himself, thereby forming a foundation to build upon and this was what just happened.
As the rulers of this seamount, it was a given that the Crocodiles already developed an innate sense of superiority towards all the other sea creatures here.
This was what Sebastian took advantage of. Apart from anatomy, he didn't have talents for a lot of things when he was still a human but provoking other people was something that he was really really good at.
His talent at it was so terrifying that he could even provoke his pet, it was such provocation that led to his new variant shark pet biting him to this world. And here in Oceania, he found that such talent was highly useful.