Maeve

The main central heroine. Maeve is a homunculus created from Theo's sperm and she requires his sperm to be injected into her often in order to survive. She is his lovely daughter and will do whatever Theo asks. How she grows up is entirely up to you!

She starts out as a child in a tank, grows up in a month into a teen, and in a second month she grows into a young adult who can go outside and join Theo on his adventures.