"What's an ottsel?"

"Don't I want to know. They talk. The one I know won't shut up."

"But not about, say, where they come from or anything?"

"They don't look alien but then neither do you. I haven't asked, the one I know lies for fun."

"Charming. Okay, thanks." He puts the models aside. Reads the bio textbook.

The biology book begins by explaining the concepts of phylogenetic taxonomy and evolution. There's a two-page spread of the tree of life, followed by a brief discussion of what phylogenetic groupings (like "fungus", "bird" or "reptile") are useful for and when paraphyletic groupings (like "arthropod", "plant" or "mammal") can be more useful. The book takes pains to clarify that this phylogenetic taxonomy is based primarily on observable, current genetic similarity; if, as is extremely plausible, the Precursors created all life, they nonetheless created it in such a way that it fits into this tree and more genetically "related" species are more likely to have similar reactions to drugs and be similar in their internal anatomy. Then the book explains the concept of a food web and illustrates with a sample one.

Eventually, after a disclaimer that none of this necessarily applies to metal heads, the book gets into more contingent facts about life on this planet. A lot of it is like Earth biology: the local people have cells, they have blood and lymph, they have organs recognizable as livers and hearts and stomachs, and they run it all on ATP. But they don't have a separate mitochondrial genome and their blood and bones have cells that are specialized at carrying and storing eco. Most species have the ability to draw energy from eco, instead of or in addition to things like food and oxygen, but the systems for that are woefully inadequate to the energy needs of large, active species, and in some cases animals can survive having mutations that make those systems nonfunctional.

And then it goes on to explain how photosynthesis works, which is not notably different from how photosynthesis works on Earth.

At one point Torn interrupts to let him know the Shadow is coming over soon and wants to meet Cam.

"Sure, I can put this down when he gets here.'

In the time it takes the Shadow to arrive, the guy handling food distribution stops by for another load and heads out again.

And then the Shadow arrives. He is the green-skinned person Torn knows. He is currently wearing his hair up and wrapped around an entire log, the ends of which are just poking out from what appears to be a sack that has tiny sprouts and mushrooms growing from it.

"Hello," he says. "You must be Cam."

"Hello, that's me. Interesting updo."

"Why, thank you. I find it helps me keep the natural world on my mind, so to speak. Anyway, I'm told you can make just about anything except eco and that you've been very helpful to the cause. I thought it would be... interesting to talk you about your goals."

"Eternal flourishing of all sapient beings everywhere."

"Eternal, hm? I suppose we wouldn't have to worry about the food chain or running out of planets."

"You wouldn't! It's great!"

"And you intend to stay here and fill the universe with eternally flourishing beings?"

"I mean, I have to do something about your ongoing metal head conflict first and there might be logistical issues with my remaining here for always but in the broad strokes sure."

"Aha. What sort of logistical issues?"

"I need to be summoned, so if my summoner is no longer summoning me, poof. I could probably come back just fine with someone else summoning me, though, I'm just not sure - see, if it were possible for people here to summon us then it's very odd for this to be the first time it's happened."

"Bizarre. How does a summoner summon you and how would your current summoner stop?"

"I can make you pre-print circles to lay out on the floor and fill in, and if, say, she died, that would do it."

"I'm not sure leaving something like that around is safe if the baron might raid this place. I am also asking what to avoid - I'd already be dead if you wanted that and I don't know whether to trust that all members of your species universally want the eternal flourishing of all sentient beings."

"Oh, they don't, I was planning to leave you circles that mention me by name. The usual advice back home is not to draw on the floor; more specifically you don't want any diagrams roughly circular referring in any language to summoning anything, flat on the ground with room to stand in the middle."

"It's not that surprising that it hasn't happened to anyone here before but I'm surprised it never happened to the Precursors. Speaking of which, I bet you can conjure their writings, can't you?"

"Sure, though I'll need another of those," he waves at his hardware, "to decipher the language."

"...Do you have a way to get rid of things you make?"

"No. It won't be useful to random people from here, though, I guess they could learn some materials science from disassembling it but not the contents."