I’ve found all the required purified pieces for to place in the alters but is this event something you can do over and over or is it a one and done kinda thing? Trying to decide if me and my party should try to do it now or wait until we are stronger incase we can’t kill them. Thanks for any info!

one time

Thanks!

You do it once, then you'll need to farm up the Purified key's all over again
Just like Tristam Ubers