I didn't activate the machines because I didn't know what it would do (I later found out it makes the battle easier). That battle was so long he was able to use 3 abilities during that fight. I just finished level 7 of the dungeon and Kana's. I had not actually run into a wurm yet, but had killed a few will-o-wisp's and they were super fragile, so I went with a wurm thinking a tiny dragon would be better. When it was time to pick a 2nd level ability, it was either the wurms or will-o-wisps. I chose the skeletons because I had only run into one or two phantoms and didn't find them tough. When it was time to choose what ability to pick, for the ones that summon creatures, it doesn't give a details about the creature it summons, so I just went on my experiences fighting them and what was unlocked in the bestiary. Had I known how useless those wurms would be, I wouldn't have taken that, and also I would have used the push and stun ability earlier and gotten us out of that door way where I could have taken care of that wizard much earlier. Those animal companions made a quick meal out of him though. He was barely hurt after all this time with three wurms attacking him. I used his 1st level ability that stuns and pushes enemies back in a large, wide cone which allowed me to get the animal companions through to chew on that wizard's bones. We continued fighting, bunched in the door way when Kana reached 3 chants (the most chants he's ever done in a single fight). The wizard didn't care and kept targeting Edér with bounding missiles. I summoned the wurms behind the mob and had all three attack that wizard. This was the first time Kana got to 4 chants and there were actually enemies left, and lots of them. He kept using the bounding missile spell on Edér which would bounce to two other targets and it was messing us up keeping Durance busy with healing. This skeleton wizard was in the right spot that no one with a ranged weapon could hit them due to the angle, so he was able to sit there and light up Edér and the animals. Kana was chanting and shooting from the back. Durance was keeping them healed and buffed, Aloth was casting AOE spells into the mob, Sagani and my character (Ranger) were shooting the targets our animals were attacking because they both have the ability that gives them a damage/accuracy bonus when attacking the same target. We had gotten bunched up in a doorway and Edér and two ranger companions were in the door holding back the mob. There was a skeleton wizard hanging back out where none of my ranged characters could get to him. On level 5 or 6 of the dungeon we were fighting a large group of skeletons. I took the one that summons 3 wurms, thinking that if it requires 4 chants, they should be better, but I had not been able to use it yet. The party finished everyone off while those three skeletons had barely scratched that archer. I used it once to cast behind some enemies and had all of them attack an archer. I've used the summon skeletons ability a couple of times, but they don't do much damage. The creatures he summons are next to useless too.

So far most battles have been finished before or just as he gets to 3 chants, so he rarely is able to use his abilities. I'm playing on hard difficulty and not using AI.

My character and all party members are level 7. While I was passing through my stronghold, I decided to do a few levels of the Endless Paths of Od Nua for Kana's quest.

Pillars of eternity 2 chanter summons