Between now and December 18th, different shards will see the dungeon Deceit in Felucca invaded by the archlich’s influence. Players are invited to take on arisen undead and get some archlich treasure in the process while also making sure other players don’t slay them for their goodies. Every weekend will see a different shard kick off the event, so players will want to read the schedule for all of the details.
Content retrieved from: https://massivelyop.com/2022/10/14/ultima-online-is-running-pvp-weekend-events-from-now-until-december/.