I wonder - can it be the Highest Logic in all that good_NPC_killing_for_Experiece_points? May be the sense is that one should resist the temptation to kill somebody good? You know, you can't surely say whether you are really good if there is no temptation to do bad things
As to your question - there's nobody across the sea, that must not be killed. May be except the first mermaid you'll meet and Oracle - I do not know whether it's possible to kill that Oracle in underwater city - but I'll better warn you (just in case
) - talk to her
Actually it seems to me in the whole game there is only one creature whose killing can prevent the game ending - it's dragon (if you didn't get the sword).
------------------
Sincerely Yours,
Tanda