marlena is so far the oldest vampire in the game, even older than the king, so she's pretty controlled at this point. in fact, she's very political and in the public awareness and has, as far as she is able, the general public assuming that she's all for mainstreaming and vampires-aren't-that-bad, when she actually hates trublood and tends to feed off glamoured or willing humans. what goes on behind closed doors is one thing, but she doesn't appreciate vampires in her territory running wild. generally speaking, she tends to rely on her wits and power, but she has been known to slap around younger vampires who behave insubordinately if they do push her temper. in short, she'd be making sure that mari would be keeping a metaphoric tight leash on nikolas.