IyoReport
English：Iyo · Characters
Second in command of the Machinists, and the P4-unit Skeleton who handles outsiders at the Science HQ in World's End. He wrote many entries in the Tech Hunter's Notes series — and, to a Skeleton player, admits he is keeping something from Finch.
Iyo is the second in command of the Machinists, a P4-unit Skeleton stationed in the Science HQ at World's End. Finch, the faction's head, refers to him as his "assistant".
The face they show outsiders
The Machinists are scholars who have committed themselves to researching the history of the world and recovering lost technology, then writing it up in books so the knowledge spreads. The scholars themselves cannot survive outside the walls — the actual ruin-crawling is done by the Tech Hunters.
Iyo sits in the middle of that arrangement. He holds diplomatic status, which effectively makes him the university's window on the outside world. The player can talk to him directly and ask what the Science HQ is for and what the Machinists actually do. He is also the author behind many entries in the Tech Hunter's Notes series — the in-game books that serve as a beginner's guide to this world.
He is hiding something from Finch
There is a line of Iyo's that almost never fires: if the player character is a Skeleton and presses him, he says this.
Look, you don't need to worry... no one will ever know the truth. As long as I am Finch's second-in-command, I will see to that myself.
The game never reveals what that truth is. The wiki notes only this much: Iyo appears to be keeping something from Finch and from the Machinists as a whole, and he intends to go on doing so.
The name
The wiki records two possible Japanese readings. One is 葦陽 (iyō), a common gender-neutral given name. The other is 異様 (iyō), meaning "strange" or "bizarre" — which, if intended, reads as a direct comment on his evasiveness. Both are speculation; the game offers no answer.