You can buy ropes in the town - look for the stalls on the right hand side of the map, near the magic shop.
You can also cut down vines and use those as rope. (That costs HP).
A) Murder would require Aura to be badly corrupted, and the corruption influences her ablity to suspect Alica.
B) See what happened to the last demon king.
Steam and Itch are seperate. That means, if you really want a steam version, you need to buy the game again...
There are a bunch of monsters that drop it. I.e. the big wolf in the southern part of the forrest of runes, any minataurs and probably a few others.
