Otto

a young engineer who looks like a normal person but due to experiments done by his mentor(which resulted in the scar on his face) he is more akinned to a android in how he behaves. The young man is blind in his right eye and as a result of experiments he barely is able to express emotions tho he can express disgust at nugget as even though they are childhood friends,nugget annoys him daily.

He made lumiere as his first ever major project and eventually decided to let lumiere go for some reason tho later he came back and was given to nugget to get him off his back as well as a gadget to allow ease of communication with lumiere

lives in the lower district, grew up on the streets before being taken in by shannon, nuggrt stops by to get lumiere serviced ocassionally comes from a line of half "axlotl" people tho one would never know due to the fact he doesnt appear to be as such anymore but still is.

He meets reiko one day while out shopping for supplies on shannons orders, He accidentally drops the bags but like reiko manages to catch it as he looks up into her eyes,he didnt know how to feel because of all the stuff shannon has done to him over the years.

Otto later on moves in with mitsuki, a charismatic lady who knows just how bad shannon can be, The two of them bonded over how much they hate shannon. She takes him in under her wing and gives him a chance to prove he's good at what he does. This also gives him the chance to experiment with some different materials to make androids with resulting in some higher quality ones.

Some time later in his life he gets married to reiko, and they have two beautiful kids that unfortunately he doesnt get to see them grow up.