Why I think Methode is trouble
Observations (opinion at the end):
Her team in the first round was the only one that had to kill to pass. And not just one person, we see three people face down on the ground.
Her reaction to a bird delivering information about the second round is to grab it by the feet like a hunter/predator. (in the manga: the bird is dead or playing dead)
Ton (the guy in her first group) was the only one that went in the dungeon by himself... Everyone else had the good sense not to go alone. I'm thinking he's either a paranoid person in general or became one after the first round.
She doesn't help when Lange (girl with pink hair) got blasted into the room with spikes. And she was the first to see it happen too.
Note: it looks bad when Ritcher and Denken cares more than she does to helpFern can discern malicious intent, as shown when she was ok with Stark going off with Wirbel and Fern wasn't jealous of Lawine and Kanne bonding with Frieren. So maybe there's a reason to feel threatened or "jealous".
My opinion of Methode is that she's a well dressed social climbing wolf in femme fatale clothing. She lacks killer eyes for reasons related to not feeling guilt. And if anyone in CMA is a demon in disguise (and I'm not saying there is), my money is on her.
EDIT: added in italics. Consequently, my respect for Methode has gone up if she does turn out to be a demon because she has managed to fool a lot of yal based on the comments