Can someone tell me if this is worth continuing...

Im not actually sure about that too. The story and art are pertty good, but the charecters lack personality and feel sorta dulll.

I wouldn't say dull. How to put it? Its very obvious that they are trying to keep their emotions in because they have a mix of depression and PTSD from all the tragic events. They are also afraid of being hurt more. As the MC remarked when she met the Madame again, she seemed even more cold and distant than she was before the last tragedy (I would specify which but it's pretty obvious if you read and spoiler territory if you don't). So in order for there not to be a "dull" character, I guess they would have not to had their whole family die or about to be killed. So far we've only seen Lily like that.

I think its more than their personalities being cold and distant, but in my eyes the majority of the characters look the same but in different colours and hair lengths...