Hank didn't see any harm in mermaids, though he was also from a world where people didn't even believe mermaids existed, so to him he was just in awe of them. He couldn't imagine being frightened of one, now dragons, there was something to be frightened of. Mermaids seemed quite possibly the least sensical thing to be scared of. He supposed though he could understand why some might want to hunt them though, he remembered how in his world men were often drawn to hunting rare things, it was why there were animal species going extinct, something he didn't miss at all about the realm he had been born in.
"Well, anyone who thinks mermaids should be feared are fools, and any time you need a friend or ally, you can count on me." He supposed it wouldn't mean much, since she couldn't leave the water and he wasn't always by the water, but just the same, to him being a knight meant honouring your word and as far as he was concerned, if Ariel ever needed anything in the future, he would gladly be there for her if he could be. He was about to turn and walk away when he heard her call back to him. He turned and took the stone she offered him, it was beautiful really, the way the waters had smoothed and polished it. He smiled and nodded, he hadn't been expecting anything in return for the help except a thank you, so the token was appreciated.
"I Will, thank you Ariel......... safe travels......." And with that he headed back to the castle, slipping the stone in his pocket.