This type of episode featuring a story entirely about a side character is called a "lower deck episode," after a Star Trek Next Generation episode called "Lower Decks." (Episode 167)
I'm speechless. The acting, the heart - wow. This episode is what all television should aspire to be. I love this show for its comedy - but this episode was a long overdue dramatic tribute to Yuki, and I'm so glad they did it. My hope is that the reveal about Yuki's past (and present) will play in future episodes.
