These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Bertrand can be incredibly cunning, attempting to kill Erin and frame Ingrid to stop her distracting Vlad from his studies. Even when the plan fails, Vlad and Erin still believe Ingrid was responsible - to the extent that they apologise to Bertrand for suspecting him!
He seems somewhat less so, admittedly, after he is Out-Gambitted by the Count, who blames him for the actions of new Vlad.
Also, Vlad in series 3, especially when he goes bad.
Count Dracula: How do I know I can trust you?
Vlad: Oh great, after all these years I'm finally the son you want me to be and you don't trust me. Make up your mind, Daddy. Which Vlad do you want? The old fangless wimp you could trust with your grandmother or me?