It’s a legit style of helmet. They’re called frog-mouth helmets.
And if it rains?
Try your best not to drown.
But in reality unless it’s pouring it’ll be fine. The helmet would just drain out the bottom into your breastplate area. But you weren’t likely to be in a rainstorm in this type of helmet. These were mostly used for jousting in tournaments since the knight can’t really turn their heads when they wear these. The lack of visibility would probably be a death sentence in actual combat. Since they were used in tourneys you were less likely to be out in the rain with this since jousting tourneys aren’t generally held in the rain.
I would have assumed it was a pug.
I think we are missing the most important part here; that the cat is standing on its own sabatons
“And just when do you expect Sir Fluffins is likely to engage in battle?”
“That depends on just how much you continue to test me so.”
Uhhm achchuly, this likely is referring to the pictured knight being a simp.