Yoshitsune Miyamoto is an engineer testing out Deunan's mecha 42 minutes into the 2003 film.
Besides building the mechas he also has an interest in cyborgs, although Briareos initially turns down his offer for inspection based on 'shyness'.
Yoshitsune comes through later on, pulling the pair of heroes out of the fire a couple times.
In the OVA, while not addressed by name or having his voice credited (in the English release, anyway), a male with some speaking lines is seen shadowing Hitomi while she's getting drunk at the bar, as well as sitting beside her at the end.
In the 2003 film, he expresses at one point to Deunan that Bioroids feel love too, even if it isn't as strongly as humans do. He then says to protect Hitomi, implying that he is also a Bioroid and that he loves her to some degree. Hitomi had expressed curiosity about love and wanted to be able to feel it. She wonders this at a bar scene directly before they go off to visit Miyamoto's workshop.
At the workshop when Deunan is being fitted for her mecha, Hitomi kids Yoshitsune not to worry about her due to her being a fit soldier, in spite of women generally having trouble with the mecha. The way she words it might actually be jealousy of the attention Deunan was getting from Yoshitsune.