[quote=@Hael]
<Snipped quote by Scarifar>

THE OCEANS, THE MOST POWERFUL THING IN THE UNIVERSE (dramatic echo)!!!

Alright, but what sort of thing would he accept? Undasis has, like, [i]all[/i] of the pearls and tons of seafood, but that's it in terms of items.

Kraken could potentially be a good ally, if he feels like he owes you something
[/quote]

Up to you to try to convince Ferghus. Even I'm not sure what could convince Ferghus to work for a water God. 

Hmm... I'd suggest giving Ferghus a unique item. Something that can be used for some purpose that Ferghus would need fulfilled. Beyond that, the rest is up to you.