Yumichika Ayasegawa (綾瀬川 弓親, Ayasegawa Yumichika) is the 3rd Seat officer and former 5th Seat officer in the 11th Division of the Gotei 13, under Captain Kenpachi Zaraki.
- Whenever he uses an Artificial soul to leave his Gigai, his personality changes to a rather violent and irritable one. According to an omake, this seems to be Yachiru's doing.
- Despite wisteria purple being Ruri'iro Kujaku's least favorite color, the hilt of Yumichika's Zanpakutō is wisteria purple. It should also be noted that while Yumichika's eyes are purple in color, in conjunction with his Zanpakutō, when calling forth his true Shikai, Yumichika's eyes and Ruri'iro Kujaku's blade glow azure blue.
- In the English dub of the anime, Yumichika states that his Zanpakutō's favorite color is sapphire, as opposed to azure, and that its least favorite color is lavender, as opposed to wisteria.
- In the popularity polls, Yumichika has gone up in each poll, placing 34th (tying with Yuzu Kurosaki) in the 2nd, 21st in the 3rd and 13th in the 4th.
- His Zanpakutō(s), Ruri'iro Kujaku placed 14th, while Fuji Kujaku placed 27th, tying with Ikkaku's Ryūmon Hōzukimaru.
- Yumichika has written Are you okay with that? and Good morning to you for the Seireitei Communication
- (To Ganju Shiba) "It's time. I'll let you choose. Would you rather I kill you, or would you like to jump into that pit and die? Please look this way and show me your expression. I want to see just how ugly you can get. Doesn't matter which one you choose, you'll still die either way. I can't take it when people are faced with a life and death situation and they don't know what to do."
- (To Ganju Shiba) "This is inevitable, I guess. Ugly people are always jealous of pretty people. It's only natural."
- (To Ganju Shiba) "If you were a little bit less ugly, I might have spared your life."
- (To Ganju Shiba) "Be sure not to make the same mistake again when you reincarnate. Ugly things are completely worthless. Since you're already ugly, I'll give you a clean, pretty death to compensate."
- (To Shūhei Hisagi) "I haven't lost yet! I'm sorry, but you have to be dead for it to be considered a loss in the Eleventh Division."
- (To Shūhei Hisagi) "It seems that you don't understand the 11th Division at all. We're all gonna die eventually, so we fight before we do! That's what we're all about!"
- (To Keigo Asano about Ikkaku Madarame) "Just look at that; that overjoyed look on his face. Ikkaku is having so much fun. After such a long time, he's able to fight a strong opponent. 'We must help each other at all costs'--it's not like that. You see, with us, it's 'We must not help each other at all costs'."
- (To Charlotte Chuhlhourne) "I refuse to look upon something so hideous."
- (To Charlotte Chuhlhourne) "Rival, huh? You talk like you've acknowledged my strength, but I'm not interested in flattery from someone with such a messed-up hairstyle as that."
- (To Charlotte Chuhlhourne) "I'm a member of the Eleventh Division - the Gotei 13's specialized combat division. It's full of idiots obsessed with putting their lives on the line. Thanks to the style of our Division, there's always been a kind of unwritten rule that all our Zanpakutō have to be direct-combat types. Just having a Kidō-type Zanpakutō is enough to get a guy labelled a coward. I don't want any of my fellows in the Eleventh Division to see this Zanpakutō's ability. Especially not Ikkaku or my captain. That's why I had to thank you when you concealed us within the barrier. If you had not used that technique, then no matter what happened in this battle, I would never have released my Zanpakutō. Even if I were to lose and die at your hands."
- (To Ruri'iro Kujaku) "I never regret anything. That's just the way that I do battle."
- (To Ruri'iro Kujaku) "I would rather die right now than have your Shikai seen by others, Ruri'iro Kujaku. But that's not all there is to it. If I don't use Ruri'iro Kujaku, then I will use whatever it takes to win, and that is my aesthetic."