Lupin's character development and why Snape's pseudonym?

[a_svirn]

No: HPFGUIDX 135698

lindseyharrisst wrote:
<huuge snip> 
> My point, though, is WHY did snape start caling himself 
> this - yes, his mother was a "prince" and he was a half blood, but 
> why give yourself a pseudonym, especially one that highlights 
> something that (presumably, because he was a slytherin and 
preparing 
> to be a DE) he was not proud of?
> 
>
I've got a companion question to yours: why does Snape speak about 
himself in the third person when he calls himself by his proper name 
and in the first person when he calls himself "HBP"? In OotP 
Dumbledore in a private conversation with Harry stated that 
he "trusts Severus Snape". In "Spinner's End" Snape quotes him 
verbatim: he says, "Dumbledore trusts Severus Snape". Why couldn't 
he say "DD trusts me"? And during their confrontation with Harry in 
the end of HBP Snape says "I, the Half-Blood Prince". I think this 
use of grammar must be significant, but in what way, I wonder? 

a_svirn (baffled)