[Excuse Byleth as he goes through a series of 'huh?' and 'oh' and 'wait, my birthday???', which manifested as him staring blankly at Felix for about six solid seconds.]

Oh. Well, yes. You can never have too many knives.

[He nodded slowly at this bit of wisdom. Ever a maxim of a mercenary: always have knives.]

But to be honest, I had completely- [not known] -forgotten about my birthday. It's not often celebrated.