There's a lot we don't know! The author in the last comment said that he has postponed the appearance of a new character for now, because there are enough meaningful events in the game! It seems to me that this is one of the messengers of Clara's father! After all, for some reason we were shown his physiognomy. If Clara's dad was involved in crime and drugs, then maybe he knows Leon's father and then there may be surprises in the plot?
Don't remember most of the beginning of the game. Believe primarily it was about protecting Alan. So his wife was sent to infiltrate the organization. Think that was correct, If I am wrong then correct me. With that belief in mind I had a theory about Anna again theory/opinion. Anna is the same as Clara.
Reasons for theory:
1. Nothing is really known about her any real info we get we get from a unreliable source (Leon) who has his own agenda. Info could be hidden to protect her cover due to agency doesn't know who to trust Clara and Leon included.
2. She is cunning and bold for just an assistant. Clara is a killer most people would be hesitant about messing with her knowing that. Anna has provoked and been very aggressive towards her without any fear. Which counters her nice, timid, shy and naive personality she shows people.
3. If Alan is in danger Clara and Leon are not physically there to protect him. Sure he is probably being watched by the agency but what can they do if all hell breaks loose. All he has is his little Assistant. Alan goes walking around outside and just wandering around. The people that want to harm him most likely know what he looks like. Going with line 2 she would be the perfect protector because no one would see her as a threat and no one knows her.
This is just my theory/opinion. That theory could change if I got the premise of the game wrong. For me it fits for a spy/espionage situation.