Episode 12 is another mixed canon/filler episode that concludes the Anita filler subarc that's only animated in the 1999. I really love how this parallel between Anita (avenger) and Killua (target) also plays a role in foreshadowing what's to come with Kurapika and the Spiders
This episode helps unravel more aspects of Gon's curiosity and acceptance of many challenges whilst displaying Killua's trauma (induced by the needle implanted in his head by illumi) of growing up as an assassin and being wired to quit when the objective exceeds his capabilities
Assassin mode Killua in the 99 just basks in the dark color palettes of the time
I loved Killua's response to Anita bc it was a double edged statement that also applies to himself, so it's like he's speaking from both a place of understanding of her pain of accepting the truth of their families prosperity while also feeling the guilt/shame that comes with it
The wonderful ppl at Nippon knew perfectly well how to implement peak filler content within the canon episodes to build one of the series main driving forces in Killua. Anita was a wonderful foil for Killua to showcase more of his own assassin families dynamics
Gon is also playing an integral role in helping Killua find more value in himself as opposed to letting himself be crushed by his lack of human connections being born into assassinhood. Gon is the guiding light for Killua to break out of his shell of having no worth to anyone
I will never take you out of my top MC's again you damn lighting rod