cthulhu said:
Yes, after all, for all his greatness, Fu is just a pesky human, an unusually talented member of a race of hairless monkeys, destined to be wiped out by the Great Old Ones.
Right.
I've always wondered about that; after all, we are more advanced than rhinoviruses in virtually all ways and yet the common cold has proven damnably hard to eradicate.
However, I think that the answer Yogi gives is naturally correct, with the caveat that Fu never does anything for
only one reason.
In this case, it is very important that Sandokan know the Black Naga is coming, that the Black Naga cannot be killed by normal weapons such as a Japanese submachinegun, and that the Sandokan must (and hopefully can) prepare himself to fight the Black Naga using the techniques of Silat and the enchanted knife.
Since Sandokan is a fairly intelligent person whom Fu Manchu presumably respects in some small measure, it is therefore important that Fu explain
why all the things in the above sentence are true. Sandokan must know that the knife is enchanted, that the Black Naga is real, that the Black Naga is a supernatural entity immune to normal weapons, and so forth.
Most of Fu's lengthy explanation involves either giving Sandokan essential information, or explaining why that essential information is true in a way that will satisfy him. This is itself an important goal, because it is vitally important that Sandokan not waste time asking stupid questions or panicking when he
should be paying attention to the Black Naga.
Which is why Fu is deigning to actually answer someone's questions rather than telling him to shut up, which is much more normal behavior for him. We can observe this dynamic elsewhere: Fu
does sometimes explain himself, but only to people he respects and in situations where there are reasons to do so (such as psychological warfare).