Giant Enemy Crabs: The tennoa are merely crablike – radially symmetrical, for a start – and breathe chlorine, but since their obligate utilitarianism puts them at odds with the rest of the Worlds at predictably regular intervals, well, they can play this one pretty straight sometimes even so.
Most of the crab-bots are pretty chill, though.
I’m very curious about these guys, indeed. I’m having difficulty picturing what [i]obligate utilitarianism[/i] even looks like, in fact.
Mostly, it looks like dealing with a pragmatic sociopath with a poor grasp of long-term consequences.
The tennoa, basically, can’t do ethics or other such considerations, be they deontic, arêtaic, or other. They are compelled to act in their perceived self-interest or that of their in-group (typically in that order) all the time, and find it very difficult to stretch their instincts far enough to get much enlightened into that self-interest, even if it occurs to them to do so. This makes them somewhat awkward to deal with for most people, because as soon as they perceive it to be in their interest to break a contract, betray an ally, or murderize an obstruction to their plans, etc., etc., they’ll do it without blinking.
(Well, actually, they don’t have the necessary body parts to blink anyway, but you know what I mean.)
Peaceful relations with the tennoa, for example, chiefly rest on convincing them on an ongoing basis that it is in their perceived self-interest for the IN not to drop BFRs on them. On a smaller scale, guaranteeing deals with them in general rests on ensuring that there are very bad consequences for breaking them which are not only promised, but backed up by someone who can make those consequences stick. Trading with them, therefore, tends to be something of a specialized area…