What is the silver knife's signifigance that Matt has on him, somehow having to do with the Traveller in him or Travellers in general?
I'm thinking, since the Traveller in Matt still is alive, these "silver knives" (that I could swear Damon may have possibly thrown into another one when fighting in last week's episode "506") act in someway much like Amara acts as an anchor for the otherside and all supernatural beings crossing over. Perhaps that knife keeps the Travellers "alive" in this realm even IF they die (and it may be why they have their name: "The Travellers"). Their names, while interpreted at first to be gypsy like (and they may in fact have that type of lifestyle; but, when Tessa was at the alter, it sure looked like they may have--at least at some point--had their own little place to call home) maybe it has more to do with how they use their magic and "live". Maybe they use those knives as temporary anchor points while they completely transfer or "travel" into another persons body (sending the other person to their dying body). Or they could even be a protection of some type from various types of magic, one I can think of right off the top of my head is some type of "waypoint" used to get past the otherside Tessa has created for when they truly die.
Either way, those daggers (or dagger, but I'm pretty confident that the other guy had the same dagger on him) are very important to the Travellers and if he was willing to make himself known to matt and threaten him...it must be a matter of life or death or something dealing with your very essence (or magic).
Outside chances could make them defensive or offensive artifacts of some kind, but once everyone finds out what exactly they are; it'll be neat if they now have some new toys to play with and to add to their arsenal (as I've always liked the existence of cursed, blessed, and magical items...I only wish more would show up and that they could use them--making human charcaters potentially very interesting quickly...just like the Gilbert ring's).
But, the fact that the Traveller in Matt is "alive" and the vampire who worked with him and had Katherine for awhile said that she would make it "permanent" leads me to believe that indeed somehow (since it isn't the anchor) it is his "anchor".
Anyway, throw out any other ideas. Or reasons to agree/disagree with my idea or modify it.