Tenshi Okumura, it seemed, had an unspoken weakness. One not covered by his stat screen or that strange introduction dialog.
He was afraid of thunder storms.
The fact that he handled himself so well this long was admirable to Isabelle in retrospect. She, personally, would have found it much more frightening to be out in the rain in that carriage, but he'd kept his cool so well!
Maybe he was just in his guardian mode and keeping calm even if he was frightened.
Whatever the reason for his ability to keep his calm before, it didn't seem to extend to the moment when lightning struck and split a tree just outside the window.
Tenshi had been in the middle of trying to undress, lifting a shirt over his head, and he startled much like Snowball did earlier.
Also like Snowball, he scrambled into bed and cuddled up against Isabelle, shaking like a leaf. With impressive speed and accuracy, in fact.