The anime gives so little love to Maryelle compared to the light novel that I had to give her some more of it here.
Light Novel Maryelle vs. Anime Maryelle:
The anime exaggerates her spaciness/upbeat personality and downplays her intelligence/serious moments.
The anime removes basically anything that will give Naotsugu a serious moment.
In the light novel, Shiroe and Henrietta don't call Maryelle "spacey" and pile on paperwork for her to do, Shiroe instead praises Maryelle's motivational abilities while Maryelle praises Henrietta, and Henrietta praises Shiroe.
In the light novel, Maryelle goes out of her way to find Shiroe herself to make sure he's okay, instead of calling him to her guild hall through Telepathy. She also makes it clear that her cheery nature when they meet her was mostly an act she was putting up to make the others feel more at ease. The anime doesn't make this obvious, although it's suggested by her serious expression when they actually settle down to talk.
She also meets him and Naotsugu before they meet Akatsuki; she finds him on the first day of the Catastrophe whereas Akatsuki meets them around five days after.
During her conversation with Shiroe and Naotsugu about the situation, she's already figuring out the logistics of traveling to Susukino to retrieve Serara while hiding this fact from the two.
The whole doting on Akatsuki and hyperactiveness around Naotsugu when they first meet her is all anime-only. The first time we see Akatsuki and Maryelle interact in the light novel is when they're talking about going to Susukino, and it's a very serious conversation.
In the light novel, she makes a point not to be touchy-feely with Shiroe because he's uncomfortable with personal relationships and she's aware of that. Her first action in the anime, on the other hand, is to glomp him.
Maryelle is a lot like Kanami, in that they're both catalysts for Shiroe to take action. However, Kanami's arguably spacier and more whimsical than Maryelle is, since Kanami just goes "LOL what is thinking when SHIROE can do it for me" while Maryelle gathered information on her own before looking for Shiroe and pooling their information.
For a thread called the "Maryelle Appreaciation Thread" I noticed a noticably notable lack of any noticable appreciatioin of the noteworthy Maryelle (the very word note now makes me wish to bash my head against a wall). While I do find it interesting how the anime essentially dumbed her down to make it easier for the pilot to be digested by a wide audience via the use altering of a character with widely known and accepted anime tropes, there is no appreaciation.
I cam here expecting at least one "Yeah... Maryelle's pretty damn dope" and what did I get? An interesting article which contrasts the anime and the light novel! Not what I came here for.
Tetra-chan is better than Marielle! She says so! lol
Everyone (or at least several people) were "dumbed down" in the anime.
^^; Even the light novel puts down Marielle's intellegence (I'm pretty sure Henrietta did at one point), but she's not a moron. She might not be Shiroe smart, but she's good at dealing with people (not manipulating them, but helping and befriending them). She's friendly and helpful.
For the rescue of Serara, I can see her saying "She should be here with us. We can't leave her all alone up there." but I think it would be Henrietta that would do most of the planning and such. Henrietta might even have mentioned it to Marie when she was heading out to see Shrioe, that in their exchange of info, check out about travel. (or whateverit was exactly she talked about with Shiroe & Naotsugu, I don't remember off-hand).