The reward list is not public but you can just ask around and see what items players have gotten so far.

As for the event itself, it is pretty much a cheap copy of what we did last year. A Halloween-styled area with monsters you have to kill to collect 50 rotting skulls. These skulls can then be handed in to Beast for a random reward. To activate the warp to Beast you will have to trigger all seven switches in the area.

This can be done once per Faldon day. Citizens obviously have a better chance at getting something nice than Peasants.

What I'm missing is basically rewards list and start/end of the event.

If there is some kind of guide out there for this years event, I'd appriciate if someone could point me in the right direction.