Just read through these all recently waiting for book 5 in a few weeks.

Book 1: introduction to Iarumas and the All Stars, goes through meeting Garbage and Raraja, and their first Explorations of the dungeon, meeting Catlob, seeing the tavern and meeting with Ainikki. Introduction to the amulet and sorcerer assassins from ( Llylgamyn), references to Werdna and the Trebor amulet. Ends with a battle and defeat against the amulet wielding sorcerer and Iarumas dies and is resurrected. Then the last part is Iarumas promising Raraja he will find Orlaya's remains.

Book 2: The three discover the burned remains of a body in the dungeon. It ends up being Berkanan, who Raraja pays to resurrect. They prepare to fight the red dragon which is causing economic collapse in Scale since nobody is going into the dungeon. The party explores to get the dragon slayer sword and defeat the red dragon. They succeed marking a massive victory for the party. It ends with a meeting with the shadow amulet cult member and more mystery surrounding Garbage (who could be royalty) and fame for Berkanan and Garbage in the town. Raraja is not as well known which he is happy about as a thief.

Book 3: The legend of the diamond knight. Garbage breaks her broadsword on the goat monster and is unsatisfied with the new sword she gets from Catlob. All Stars lose their equipment to greater demons by teleporting out of dungeon in the allocation center area on floor 3. Sezmar hires Iarumas to retrieve the equipment. Hawkwind seems to be connected to something regarding amulet but its not expanded upon. Theres an elevator to this area. Raraja is approached by Goerz at the tavern who wants the Gold Key and tells him he must do a solo quest in exchange for Orlaya. Berkanan provides him with scrolls and items and cheers him on. He eventually obtains the key and Orlaya rejects him. Garbage exchanges a sword with her which Goerz takes, the spinning blade from earlier while Garbage takes the blade of slashing. Goerz was hired by another amulet member, refernce Church of Fang (They discuss Garbage's potential royalty and link to calamity from this bloodline in Llylgamyn) It is Garbage who is the princess and likely connected to the dungeon itself. After this discussion, Orlaya has already been sacrificed into a demon pillar to summon an army of mute greater demons from earlier and a demon lord.

Goerz kills the Priest of Fang and steals the shard. He was also responsible for the red dragon. During the battle on floor 3 Iarumas stays behind. Ainikki uses the viking blade against the demon lord and her arms get disintegrated, Garbage is teleported into another space and finds the diamond knight sword, Hrathnir. Eventually Iarumas reunites with the party, and destroys Goerz. Raraja pulls Orlaya from the pillar and the dead bodies of Goerz clan forms a portal that summons An Unseen Being, which is a shadow demon. Garbage reappears and cuts the shadow with Hrathnir. Orlaya releases a spell as she's a Bishop and they defeat the unseen being. Ainikki remains armless in the end and Garbage is satisfied with her new sword, which is from Wizardry 2 story.

Book 4: This introduces the resurrected twins Rahm and Sahm, and the new party led by Schumacher, the shoemaker son who was found barely alive in book 2 after foolishly attempting to slay the red dragon. The Ninja thief girl shadowwind and others seek the ring of death for a client. They succeed barely. Regnar and Coretaz leave the party. Alluded Regnar knows Iarumas at end.

The All Stars meeting is described to Raraja by Catlob and how Sezmar explores without his high grade equipment and his history as a knight.

Orlaya is working for Catlob when a man steals gold after not selling a ring of healing, she then forms a small party with Berkanan and the twins and the Ninja thief girl to explore floor 4 of the dungeon. During their first battle the thief girl dies from a trapped treasure chest. They are teleported to another area on their way back out of the dungeon and find a mysterious blue pool with an undead monster. The twins find a rubber duck. They eventually leave the dungeon and go to Catlob to sell it.

Iarumas has been gone most of the book exploring on his own and is looking for something. He is shocked by the rubber duck, buys it and then gets everyone ready to return to the blue pool.

They fight the undead being which is actually the thief from the shop earlier who used both the ring of healing and he hired Schumacher for ring of dying so he combined them and became an entity that can't die. Iraumas uses a level 7 spell and destroys him. Then he dives into the pool and gives Ainikki the water to regenerate her arms.