1. Yes, the connection to the Crystal Arch will remain as long as the Door is open (in terms of the game, it is always 'open' and if it ever ceases being that way, there will be a major gamewide announcement!).

2. Yep, monsters are totally killable, just please try not to murder every single one of them. It's fine to kill a few, as long as other players get to play with them as well!

Welcome to dwrp, also! Please let us know if you have any further questions.