Iris gets a human form and then rapidly devolves into damsel in distress. This includes a 3-5 chapter stretch of her being publicly s*xually assaulted, then a bit later in the story suddenly everyone wants her to get a boyfriend and get married. She also stops developing her combat ability and switches to a more passive support healer role.
If all of this makes anyone think she evolves from a golem into a girl and thus became weaker, ha, nope. She actually evolved from a healing golem to a holy knight type battle golem. The only explanation for the plot derailment is that the author introduced two male characters and wanted them to repeatedly save Iris because now she's a girl.