wtf?
I got 3 copies of Xiao too.
Also Altair and Eustace.
45 SSR now
I got the event boss down to around 20% before Jeanne killed herself mysteriously and the rest couldn't do much damage so I lost. Ugh.
Jeanne first ability will put a debuff on her that eats away I think 10% hp for 5 turns. Use Xiaos first ability to negate this. Jeanne third ability will kill her at the end of her 5th turn if she doesn't get fully healed by then.