I think Death 13 is one of the arcs where Eileen's loyalty to Kakyoin is really evident.
Spoilers for Death 13 below, fellows.
In the beginning Eileen is all over the baby, cooing at him "look at his little hands!" tickling him, super involved - until Kakyoin starts thrashing in his sleep and the plane crashes. Then she is alert!
Cause while everyone's ignoring the hell out of Kakyoin hoping he'll stop being so 'weird' and shit Eileen goes: "ah! A friend in need!" So she just hangs back with Kak, silently waiting for him to spill.
He's really confused by this, and so are the others. There are a couple of times when Joseph asks if she's alright "staying back there" and that "it'd make this old man really happy to have some company" as a way out, but she politely refuses.
Of course Eileen can't be by his side 24/7, so Kakyoin still gets framed as "crazy" by Mannish Boy, but y'know.
Kakyoin isn't really used to people hanging out with him?? Especially cause he can overhear the others talking about dropping him off and otherwise. Eventually he asks "Aren't you scared I'm going to hurt you?"
And Eileen raises a brow and replies "Nah, you're not the type."
"Why are you staying behind with me anyways, you don't usually walk so slow."
"I'm looking for a change of pace."
"And?"
"And you're my friend. Today's been awful and it can't be fun being by yourself, so I'm doing something about it. Do you want me to go, Kakyoin?" It's one of those rare instances where Eileen sounds stern.
"No."
"Great!"
"And Eileen?"
"Mhm?"
"Since we're friends, you can call me Noriaki."
Eileen is super frustrated too, she understands why the rest of the Crusaders are wary, the baby's mother entrusted them with her son, but someone still needs to go to bat for Noriaki. (Of course she doesn't know that woman literally just,, found the baby + wanted him outta her sight, but y'know)
Noriaki's their friend, why would they abandon him like this (she is definitely projecting)? Especially since he hurt himself?! If that isn't cause for care Eileen doesn't know what is.
Do they think alienating him will make Noriaki knock it off?
During(?) dinner when Noriaki has had enough of Mannish Boy's antics (the scorpion, eurgh) Eileen's upset when they knock him out, but has to admit she's not in the right.
The dream sequence unfolds as expected, although Eileen is relieved to tears when Noriaki's okay!
Then waking up in the morning without the memories is weird.
No cut on his arm (good, but how? Does HG have healing properties she doesn't know of?) and perky... Something definitely happened.
She'll ask later.