Bit of a nightmare to defeat. First fight that took me three tries.

You want to sneak up on him from the side, so DO NOT follow the 'cat' (Displacer Beast)! That will lead into an ambush (although also the 'dialogue' way out of the fight). Sneak up behind him and his henchmen but be careful about how you position your companions, as they WILL push you off that ledge, and it's not a nice drop. Your first goal should be to kill Yurgir, so you really do want a 'surprise' attack here.

I think if you miss on your attack, the enemies will not be 'surprised'. Then after taking care of Yurgir, you want to see how many of his troops you can push off the ledge, with either push or something like Eldritch Blast, or Thunderwave. That is just to thin things out temporarily. These guys will all hit twice, have high AC and ARE IMMUNE TO FIRE. RIP Fireball, so much for that. Ask me how I found out they are immune to fire damage.

The Displacer beast is a high priority but not a top priority. Once he has cloned himself a few times he has got to go though.

If you are thinking of taking the dialogue route, you should be ashamed of yourself.

just kil the rat king first and it will go without a fight

why was raphael so scared of this guy

i accidentally cheesed this fight.
i hid under the platform where all his minions were, in a attempt to make them all clump together in a area for me to use fireball.
then i remember i had karlach carrying the the rune powder that i kept from the towers.

so i had karlach drop it, pass he turn, i positioned myself, casted a fireball on it, it killed everyone and everything except me.
it worked.

could be because i had passive on but spoiler when i went to raphels home he was there and was a great ally in the fight runing invisible and dropping 40 damage quiet regurally

This fight currently feels impossible on tactician.

Well I learnt well to always bring one character only to walk. Realizing ambush, i just aggro them to the broken stairs and kite them

The easiest way to beat this fight on all difficutlies is to just attack the Displacer Beast with a ranged attack, without letting it run away. that will agro all minions + Yurgir and they will come to you. You can easly gateway them through the very narrow hall, even place barrels of oil or smokepowder. super easy fight, even without Meaty (the flesh golem you get from Balthasar)

His bombs are very powerful and useful in the future if picked up in combat. I managed to collect 16 bombs, maybe they drop them endlessly and he is a source of farm.