Evilutionary Biologist: It might seem, at first, that there a whole lot of these (and, indeed, that the esseli are an entire species of Evilutionary Biologists). Unfortunately for those who fancy this sort of thing, the average bioengineer is of the opinion that evolution is a hopelessly inefficient optimization process that, while it often throws up interesting traits, very often does not optimize for what the customer wants. As such, in a world of sophont beings who can, with a little prompting, put some decent parameters around what they want, a competent designer can beat evolution quite substantially more than nine times out of ten.
Now, the bioengineers may have the attitude and some of the more scientifically valid methods down pat, but while they may not match 21st-century Earth notions of bioethics – and the Monument to the Martyrs of Science is quite large – local ethical standards are firmly in place. (See the relevant sections of Blue and Orange Morality.)