No one person has two Abilities, Atsushi knows. Even if an Ability has multiple uses, or multiple forms, they’re all the same Ability in the end, and everything is tied closely together.
Which is part of the reason that turning into a tiger comes as such a surprise to him, because he already suspected he might have a different ability: seeing ghosts.
He used to be beaten for claiming to see them - the orphanage didn’t need more crying children than the living ones, and really, what wasn’t he beaten for? - so he doesn’t speak about it any longer. But he can still see them: some trying to go about their business and pretend they were still alive, most following someone they’d cared about in life. He can even hear them speak, though he knows better than to acknowledge them out loud.
As far as he can tell, tigers and ghosts have nothing to do with each other, and he has obvious proof that he can turn into a tiger. Therefore, wasn’t he just hallucinating ghosts, the entire time?
His resolve to just ignore the ‘ghosts’ is strong, but there are some habits he’s never trained himself out of. He steps around people who aren’t there and turns his head to listen to crying no one else can hear. It’s not something that someone (other than Ranpo) would pick up on his first day in the Agency, but over time, it becomes more obvious.
Today, he chooses a particularly circuitous path to get to his desk, and doesn’t realize everyone’s staring at him until he reaches it. “...What?”
“What are you doing?” Kunikida asks.
Atsushi gulps. “I don’t know what you mean?”
“Usually people choose a straight line to get to their destination, unless there’s something in the way.” Kunikida taps on his desk, impatient as usual. “You’ve been doing this since you arrived. Is it a compulsion of some kind?”
“Oh, no, it’s nothing like that! It’s just-” Atsushi hesitates, and cringes like he’s about to be beaten again, but he can’t come up with a believable lie, so- “Ghosts. I don’t like walking through them.”
“Ghosts,” Kunikida repeats, eyebrows raising. “Really.”
“That’s a new one,” Dazai says, with his usual smile. Atsushi can’t tell if he believes him or not. Probably not. “How many ghosts are in this room? Tell us about them.”
Atsushi does a quick headcount. “Six. One adult man and five children. The man is a redhead...”
For all his talk of suicide, Atsushi has never seen Dazai go paler faster.
Now he’s sure he believes him.
The adult ghost approaches Atsushi, and with a gentle smile on his face, says, “Can you tell Dazai that I’m proud of him? It’s very important that he knows.”
“Uh? Sure, I can-” Atsushi turns back to Dazai. “He says he’s proud of you, Dazai-san.”
“...Excuse me.” Dazai stands up from his desk and leaves the room.
Kunikida stares at him as he exits. “What was that all about?”