never heard of either one
Rivirine, or how ever it's spelled, is out of Stormwreck and it's one of the most powerful Special Materials in the game. It's water compressed between two walls of force and utterly immune to damage. A couple of Spells can break it, pretty much the same ones that specifically interact with Wall of Force, but it's immunity to damage make's it a great go to defensive upgrade.
And the DMGII introduced Signature Traits, they cost and do nothing mechanically. It's just added flavor fluff. Casting Grease on a
Writhing Flaming Quarterstaff is a great way to intimidate people and it would probably land a hefty circumstantial bonus to Intimidate.