Like her husband, Gertrude never made a physical appearance in the movie but a picture of her can be seen in Jorge Gutierrez's tumblr.
Gertrude was born into a very wealthy German family in Mexico City. Her family's wealth drove the ambituous Captain Mondragon to give up on courting Carmen Sanchez and pursue Gertrude, eventually he succeded and got Gertrude to marry him. Through their marriage, Captain Mondragon grew to love Gertrude with all his heart but his love wasn't enough for her  and she demanded he gave her a lavished lifestyle, which may have resulted in him and The Medal of Everlasting Life. When Gertrude found out her husband died during a fight with Chakal she knew the reason involved the medal and retreated with her daughter Matilda to her mansion in Mexico City out of guilt and left Joaquin behind in San Angel to train with General Posada.
Gertrude has brown hair like Joaquin with some streaks of grey hair done up in a beehive-like hairstyle, brown eyes and pale skin. She wears a long sleeved victorian black dress that hides her feet from view with a long sleeved button up white blouse underneath, a cameo choker necklace and pearl earrings.
She is described as being "frigid and not the most caring". She is also very materialistic since she cared more about having a lavished lifestyle than she cared about her husband. However, she did care for Captain Mondragon since she went mad with guilt when he was murdered as she blamed herself for his death due to her greed.
- She was designed by Jorge Gutierrez's wife Sandra Equihua and her design was inspired by an expensive perfume bottle.
- She taught Joaquin how to speak German.
- She married Captain Mondragon to spite her father; a powerful general.