source: https://www.pixiv.net/member_illust.php?mode=medium&illust_id=76699372

All characters depicted as 18+

Artist(s) commissioned:
shida214 https://ouo.io/L8FGm
This comic is set before the events of HSDK.
Mikumo is attacked by a kunoichi after meeting with Senzui.

DraKenTE https://viid.me/9MeV5
This comic is set during Shigure's imprisonment (just after she managed to contact Kenichi & the others).
While keeping watch over Shigure while the scientists secure/produce more restraining resin, Mikumo decides to finish their unresolved fight.

kometoze https://ouo.io/nemuu5
This comic is set just after Yomi & the Shinpaku Alliance fended off 2 Masters & the disciples of the Hachiou Executioner Blades.
Rachel challenges Renka to a fight - to settle things between them.

pakwan008 https://ouo.io/3o6LTo
This comic is set during Kenichi's time in Amsterdam.
Yomi's armed division attacks the Shinpaku Alliance.

sikretwepon https://viid.me/9MeVQ
This comic is set just after Kenichi's return from Amsterdam.
Miu & Renka have a sparring match.

MCQ07Gn https://ouo.io/UNOCRJ
Recalling how out-matched she was in their previous encounter(s), Shigure duels the female members of the 'Hachiou Executioner Blade' in preparation for her duel against Mikumo.

Nisego https://ouo.io/5pzfIF
This comic is set after Elder & Mikumo's 'date' in the final omake.
Mikumo challenges Shigure to a duel.

nufisu https://viid.me/9MeVA
After her defeat at Ma Kensei's hands, 'Mad Sword Izayoi' decides to turn to the side of good. Izayoi joins Jennifer Grey's team & now aids in covert missions.

Ai-noHikari https://viid.me/9Mexd
After graduating from high school, Renka accepts that she will never be with Kenichi. Rachel tries to console Renka in her own way.

illustraera2 https://www.rqq.co/BhvVo
This comic is set after Kenichi's graduation.
Rachel & Renka confront Rachel's abusive father.

Lentiay https://viid.me/9Mw4c
Set after Kenichi's graduation from high school.
The Kuremisago Disciples seek revenge against Miu, but end up fighting Rachel & Renka instead.

marioferro https://ouo.io/UHMqVq
Kenichi fights the Elder so that he can marry Miu.

NJClaws https://ouo.io/kLX6K4
Kenichi's family, masters, allies & acquaintances celebrate Kenichi & Miu's wedding.

Reneg30 https://viid.me/9Mwnb
Miu, Freya, Kisara, Chikage, Rachel & Renka spend some time together with their daughters.