I feel like Fuyumi should've saved Natuso, instead of Endeavor and the trio. But, like, in the worst way possible.
Ending and Natuso are actually in a even fight. Endeavor, the trio, and Fuyumi arrived from the commotion. Natuso gets distracted, Ending lands a heavy hit, and Fuyumi panics. Fuyumi goes for a "full power, no control" move (basically Snowgrave) and Ending is frozen in a block of ice with lethal hypothermia-level temperatures.
The Todoroki children have minimal screentime so I wanted to establish a few things. First, their quirk capabilities, so it seems like less of an as**pull later. Second, the more unhealthy side of Fuyumi wanting to keep her family together and safe.
And third, if possible, more of an explanation regarding civilian quirk control. Like, more Endeavor going "we need to keep Ending alive because my daughter will be arrested for murder by a non-hero," less "we need to keep Ending alive because I'm such a good guy and it's technically ok if we fail."
Actually I really like this idea and rewrite.
The todoroki kids specifically natosu and fuyumi lack screentime therefore they lack development but they, unlike rei still feel like actual characters with real flaws and realistic reactions.
The series clearly establishes both natosu and fuyumi's feelings and dynamic to their dysfunctional family.
Natosu is the rightfully angry one who tries to continually distance himself from enji and rightfully both despise him and blames him for everything like touya's death (which happend due to his neglect)
Fuyumi is the one who wants to ignore all of it so she just tries to pretend that it's not true and that she does have a happy perfect family. Fuyumi tries to live up to the image that the public expects of a hero family but she also deeply cares for her family and a part of her deeply longs to make those thoughts a reality.
It is exactly that reason that we see fuyumi trying her best to connect everyone and keep a brilliant image when todoroki invites izuku and bakugo over.
However, reality hits fuyumi hard and there are a lot of things she feels when she isn't pretending to uphold the image of a perfect daughter of a perfect family. One of the feelings being an attachment and close relationship with natsou. heck if we are being realistic I think that their relationship could be explored in an unhealthy way for example the series could show us that fuyumi and natsou are so close that it may effect their relationship with other people and its something that they slowly learn to develop out of as they trust and meet more people.
Every time we see natsou on screen fuyumi will be mentioned or be present and the same applies for fuyumi. The narrative introduces them as an inspereable pair even from early on in childhood where we see fuyumi covering natsou's ears to both of then visiting their mother and more.
Having fuyumi be the one to save natsou establish and help emphasise a lot of thing within the narrative like:
Fuyumi's strong desire to keep her family together and uphold the image of a perfect family
The ice powers that the himura's have
More world building within quirk use and heroes wanting to keep their reputation spotless at all cost
This also helps shine the dangers of being a heroes child or family member and how it can put them in danger
Also if the aftermath of the fuyumi vs ending fight is dealt correctly it can show the more corruption side of heroes specifically enji