The giant bear thing is the product of a joke Gav Thorpe (I think it was him) made, that for all the fans know, the Nicassar could be psychic polar bears or something. Basically, it meant "you don't know what they look like, nor are you going to soon". Some people took it too seriously.
The Blood Angels Codex has the "honor of warriors" stuff. The Necron Codex has the Silent King realising his army was too weak to destroy the Blood Angels, and bitterly slipping away instead of risking defeat. One of the reasons I really like that codex.