I fundamentally disagree with the rhetoric that Knives is actually a Legato abuser. If you think that Knives is forcing Legato, which leaves him no choice, and that Legato is Knives' hostage, then you've been reading the manga with your eyes closed. this is going to be a long post. sorry for my poor English.
don't get me wrong. Knives is strict with Legato. he's rude and sometimes cruel, but he's never taken away Legato's choice. Legato's choice has always been to serve Knives, but even in this service, Legato followed his own personal desires and goals, which sometimes differed from those of Knives. Knives punished Legato for trying to kill Vash, yes, it was cruel, but Knives never pursued the goal of killing Legato or breaking his will. on the contrary, Knives did nothing, even when Legato pursued his goals after the punishment with attempts to make Vash suffer. Legato asked Knives if he would be angry at his showdown with Vash, and Knives could have already killed Legato to avoid such a thing, to protect Vash so that Legato could not get to him. but Knives didn't do it. not only because he needed Legato's help (he didn't really need it that much), but because his feelings for Legato were always complex and contradictory, eventually leading to the fact that Knives simply didn't want Legato dead, even if he was angry at him and even if he didn't follow his orders.
abusers can be cruel and rude, yes, but they don't leave a chance to be someone else, leave or act the way the victim wants. and Legato was never in the victim role with Knives, because Legato had a choice. I mean… we know that Legato is stronger than Knives, right?
and Knives knows this, otherwise he wouldn't be so surprised and scared by Legato's sudden appearance. I mean, look at his look. It's fear. Knives knows how strong Legato is. his powers are enough to control his body. and I think his strength is quite enough to take at some point and say, "my lord, I'm tired, I'm leaving," and Knives couldn't do anything about it, and thats why i think that:
1) he doesn't have enough power to kill Legato. Legato would have just stopped him.
2) he would not have forced Legato, because the primary reason why he saved him in the first place was the mistreatment of Legato by humans.
Knives saved Legato on a whim, but where did this whim come from? what was it dictated by? usefulness? yes, Knives found Legato's powers useful at that time and very interesting, but this view says something else. how surprised Knives is when Legato reacts like that to death. he sees salvation, and he's grateful to Knives for that. I think Knives realized their similarities at that moment. Legato was a victim of humans whose bodily integrity had been violated. Knives wouldn't kill Legato by taking away from him what humans take away from his sisters and Vash. but yes, he would be angry and cruel. but murder and coercion are a line Knives wouldn't cross.
I also believe that Knives was not always cruel and rude to Legato. up to a certain point, he treated him well. here we can see how surprised Legato is when Knives responds to him with such rudeness. Legato probably doesn't understand this reaction from Knives. Knives probably hadn't been so rude to him before. however, I have some thoughts about why Knives behaved so rudely at that moment.
this is just my personal interpretation, but I think that at that moment Knives was literally in shock at what had happened to his body and what had happened in general. he was literally covered in a bloody mess of his own organs. he was in shock. and when he saw Legato, his tears, he felt weak, wounded, defenseless. and he felt that way in front of the human. Knives had a defensive reaction. he did not want to see Legato's tears, because he believed that there was no need to feel sorry for him, no need to cry for him, because he was stronger than humans, and more resilient. he's a superior, and humans are just cockroaches. and he doesn't need pity. Knives' rudeness was directed towards his past traumas, his fear of being weak and vulnerable in front of humans. his rudeness was not for Legato, but as if for himself. to remind himself that he's strong. If it had been Elendira or Conrad, I think Knives' reaction would have been the same. his rudeness at this moment is dictated by his injuries, fear, and principles, rather than specific feelings for Legato.
now let's talk about "Legato needs therapy. Legato needs another person." no, he doesn't need it. because that's the whole point of Legato. in his tragedy, in his doom, in his unwillingness to live. for him, the meaning of life lies in serving Knives. don't get me wrong. Legato has a strong personality. he has his own will, his own desires, his own thoughts. but he still serves Knives. he's Knives' man. Legato chose it himself. Knives didn't force him to do it. and what kind of therapy can there be on this planet? who actually works as a psychologist there? do you think Legato would want to live if he was saved by Vash? no. Legato was originally stewing in hatred of humans, he was going to carve out an entire city. In Vash, he saw himself as devoid of will, and this angered and hurt him. I don't think Legato would have survived if someone else had saved him. Legato had no will to live. Knives created his will. his will was formed when Knives saved him, because their attitudes towards humans were similar and their injuries were similar.
It is also important to note. Legato loves Knives with possessive love, not as a slave. Legato is not a slave to Knives, as I have said several times. because slaves don't have their own will, they don't have their own opinions, they don't have anything. Legato has it. and Legato wants Knives to the last drop of his blood, wants him to look only at him. Legato is obsessed with Knives so much that he is willing to act against his will, thinking that by doing so he is doing better. Legato is not in a short leash, no. he is more like those servants who act of their own free will, get punished for it, but still act of their own free will. and Knives doesn't do anything about it. i mean... he could have killed him. but he didn't. Interesting, right?
and another important point. the last one, I think.
Legato is not afraid of Knives. otherwise, he wouldn't act the way he wants to. otherwise, he wouldn't have asked if Knives would be mad if Legato killed Vash. Legato is not afraid of Knives. Knives is afraid of Legato. their relationship is very complex, ambiguous, difficult, but very interesting, because if you analyze them, you can find a lot of interesting details. their relationship is not vanilla or "and they lived happily ever after." their relationship is a pain and a tragedy. they were both doomed from birth. both were broken by humans. both needed help. Knives was too proud and scared to admit to himself that he didn't want Legato dead and that he needed him not because he was useful, but because he just needed him. It's been his whim for decades.
I think that's it. thanks for reading. I also recommend reading yuliasolsystem analyses. they are very interesting and detailed.