[godleydemon]

Yeah I just went through and found the chapter and the section it describes it, it's got no process what so ever. It's just, "She looks down and see's a childs body" kind of process lol.
Here is the small section for it from the novel.

Mountains----and even the sky covered by dust was pierced by the [Air Strike],
and was now finally ceasing.
"...Haa...haa.........haa-----!"
Due to the overuse of power, the lack of elements caused her to be unable to
maintain her natural shape----- her appearance turned into that of a young child.
Jibril held her breath and descended, into the place where her [Enemy] lost her
form and appearance.
"...Aah~...really...with this there was not even any merit in doing all that..."
----For starters, that was a battle that started just because she wanted the head
of an Ex-Machina that was taking action alone.
Because of its unique actions, her desire for its head increased even more----
and the result was [Air Strike].
Jibril was assaulted by a trembling whose meaning is unknown even to her----
Her instincts told her that that machine was a [enemy] that must be destroyed.
But, after standing calmly and looking back----she wondered.
"...I didn't got the head, all parts were blown away, and this form..."
Saying that, after looking down at herself who regressed to a young child, Jibril
released a long sigh.
"Haa~...I should report to Azriel-senpai, at least that there was a weird ExMachina----it
would be good if that muscle brain with a flower garden in it, get
even at the very least the meaning of making me use [Air Strike]..."
But----after once again looking down at herself who regressed to a young child,
she whispered with a headache.
"If I stand in front of senpai with this appearance...she won't let go of me, right..."
The small Flügel, started flying towards the horizon while troublingly flapping its
wings.
----Small. Without noticing, a too small silver circle shining----...