TSAB has found out about Puella Magi in Unadministrated World 97, and become actively involved in the case, using their best agents for that area, Nanoha Takamachi and Fate Testarossa. Usually, that means it's time for befriending!
Things don't go as planned.
A dōjinshi from Bun150, Mosome circle and four of its ten chapters can be read here.
Mado Nano Crossover provides examples of:
- Awesomeness by Analysis: Nanoha discerns Homura's power in the second time they met and first time they had a fight. She rightly concludes that if Homura's really serious, she'll be dead.
- Badass Adorable: Moemura with Homurambo personality.
- Didn't See That Coming: Chapter 2.0 starts with Fate checking Witch appearances. In there, she founds Kyoko Sakura, who should have been sealed in chapter 1.0. They then fight viciously, with Fate manages to overpower her. But then it's revealed that Kyoko she defeated is product of Rosso Fantasma. Suffice to say, she got blindsided, and you can say she's lucky that Kyoko didn't strike to kill.
- From Bad to Worse: See Nice Job Breaking It, Hero! and For Want of a Nail. Then it's revealed that TSAB High Council and Incubator are in cahoots.
- For Want of a Nail: In the timeline before the story proper, Nanoha and Fate comes directly to Homura and Madoka's aid (probably timeline 3 or 4 from Puella Magi Madoka Magica episode 10) but failed to change the situation; it ended with Nanoha making a contract with Kyubey to have sufficient power boost against Walpurgisnacht. Horrified Madoka asked Homura to resets time and save everyone. From there, Homura keeps her look, but her personality is closer to Homurambo.
- Hilarious Outtakes: The backpage shows Kyubey and Ferret-kun beat the shit out of each other.
- Nice Job Breaking It, Hero!: Kyubey specially mentions that TSAB's involvement causes Puella Magi, and by extension, Witches, to grow stronger. Even after their Soul Gem is sealed, they still appear.
- Story-Breaker Power: Homura's power. The reason she lost to Nanoha is because she was holding back.
- You Can't Fight Fate: The concept, not the character. Due to the TSAB's Dimension Interference, Soul Gems are captured and the Puella Magi are turned back into regular girls with their memories erased. However, when Witches and Puella Magi return, Kyubey explains that Cause and Effect is being enforced because the TSAB magically revoking the Wish Contract prevents Puella Magi from becoming Witches, which is necessary to avoid having Causality collapse and to maintain the circular nature of Cause and Effect. Furthermore, the TSAB only removed the "Cause" of the Contract; the Puella Magi, and not the "Effect"; their Wishes. As a result, the Contract carried on and Witches and Puella Magi came back. Even worse, due to their Interference from another Dimension, the Universe has enhanced Causality in order to maintain the Contract, resulting in Puella Magi and Witches having their magical power boosted several times, allow Puella Magi to fight evenly or even overpower the TSAB when before they were Curb Stomped, and making the TSAB forbid Nanoha from fighting Walpurgisnacht due to Its new level of strength.