Finished watching the last 4 episodes of Nisemonogatari, which covers the Tsukihi Phoenix arc. Tbh unlike Bakemonogatari and Kizumonogatari each of the arcs surrounding of the sisters isn't just that. Basically, we learn stuff about the other girls. Though honestly the only interesting stuff was with Senjougahara during the Karen Bee arc and Shinobu being heavily involved in the Tsukihi Phoenix arc. Now regarding Tsukihi Phoenix.
The big information drop within the last two episodes is that Tsukihi is possessed by an immortal bird. Neither of the sisters know of this. Of course, there is no doubt that Karen would accept Tsukihi. But for Tsukihi to know the truth would absolutely crush her. The big thing that this arc tackles is how do you deal with the real vs the fakes? For Oshino we know he cared about the balance. Meanwhile, for Kaiki he held more interest in the fake while Kaeguni believed in the real.
Much like with the Karen Bee arc, this arc really shows Koyomi showcase his role as a big brother. Much like with Karen and how she needed to be ok with being a fake hero. Essentially be a defender of justice, but to let her big brother handle the serious issues in her time of need. For Tsukihi she is more delicate and is a target of both Kaeguni and Ononoki. Regardless of her being fake or not, she is still his little sister. And no matter what, he will continually strive to protect her.
As Shinobu takes care of Ononoki, Kaeguni decides to call a retreat. I guess facing both Shinobu and a regenerating Koyomi might be a little too much for her. It does offer a little better conclusion here where their win feels more definite. As opposed to bullying Kaiki to stop his shady business.
The one interesting part is what will Koyomi do next regarding Tsukihi. It's a very delicate matter.
I would rate Nisemonogatari an 8/10. It does a good job at showcasing the bond between Koyomi and his sisters. Issues being the SoL episodes and the fan service somewhat hinder the pacing of the arcs. The toothbrush scene is the common example of this. Overall, this is still a solid entry in the
Monogatari series.