That’s about all you can do, is have your party pop defensives.
Can use the urn to stun him for X amount of seconds of a night Fae is in the group (which you are 
)
As for the 15 vs 16 thing…I’m going to assume the 15 was done last week, which was tyrannical. This week it’s fortified, so the trash mobs are all beefed up. So they’re hitting a lot harder. Goes for that Enraged Spirit as well