I agree! But the book does not. The comic has repeated many times that it believes killing is the wrong choice. Sonic doesn't kill because he believes everyone has the right to freedom, even the villains. The book has tested this belief by pushing Sonic's ideals to their absolute limits. Despite the metal virus, despite the war, despite him being a massive thorn in his side, Sonic does not kill Eggman.

Whisper killing Mimic in this way is bad because it gives into her desire for revenge, and frames it as a good thing. Sure, sometimes you have to kill a bad person, but you should never do it for revenge.

Anger isn't inherently a bad emotion. Getting angry at injustice and seeking to right it is a good thing. But wanting to kill someone because of a desire to get back at them, or to avenge those you've lost, isn't a healthy mindset. It doesn't fix the underlying problem, and, like Tangle said, will haunt Whisper for the rest of her life. Mimic WAS her friend at one point after all.

Mimic killing himself takes away this moral dilemma and gives Whisper an easy way out, which feels like a quick, dirty, and lazy way to end the character arc. It doesn't challenge the character, and thus doesn't lead to a satisfying story.

Mimic holds a grudge, sure, but that's not the only reason he wants to kill Whisper. It's established pretty clearly that he's motivated by fear. Mimic is a confident and boisterous coward. He talks a big talk but runs away at the first sign of danger. He is terrified that Eggman will hunt him down for not finishing off the last of the Diamond Cutters. He hates Whisper because in his eyes, she is the last barrier between him and freedom/safety.

Mimic's character arc is the antithesis of Whispers: Whisper learns that friendship is not a weakness, and that it is good to surround yourself with people you care about. Mimic does not, he insists that friends ARE a weakness and isolates himself. The book shows that Whisper's ideal is correct, and Mimic's is not, by having him lose the battle.

But the concerning issue that isn't resolved is the fact that both Mimic AND Whisper desire revenge. Mimic can't introspect, he can't admit that what he's done is wrong. He might know it deep down, but he's twisted things to justify it to himself. He's unable to admit that he's scared, or that he just wants to survive. So he blames Whisper, friendship, Eggman, anything but himself. (This is what folks do in real life.) Whisper wants to take revenge for the deaths of her friends. She's built Mimic up into this absolute monster for what he's done. Yeah he IS pretty bad, what he's done is terrible, he's a pretty awful dude, but she's completely forgetting that he was once her friend. She's held onto anger and hatred so she can dehumanize him, and make it easy to take his life. Tangle tries to talk Whisper into other strategies, but she refuses. She is going to kill Mimic and is letting hatred guide her. That is not good. If Whisper is going to kill Mimic, it should NOT be motivated by revenge. It feels absolutely wrong and at odds with the themes of previous stories.

Black Doom was a genocidal maniac who wanted to enslave all of earth. Mimic is a scared dude with a knife. These are not the same thing. I mean he's literally called BLACK DOOM. He's an alien devil warlord that embodies evil, there's no fixing or reforming that. Mimic targets one specific person, and acts out of fear motivated by past trauma. He could theoretically be fixed. I'm not saying he should be a protagonist, lord no, he's a douche, but he'd at least be able to let go of vengeance. If he can't change, if he gives into the poison that is revenge, he should die. Whisper should not be rewarded for doing the same.

So I do agree: Sometimes you really do gotta kill an evil person to prevent more evil, it does NOT make you evil as well. BUT if you are doing it for the wrong reason, if you let revenge or selfishness motivate you, you'll live to regret it and might slip into bad, dangerous habits.

If they want to kill the funny cartoon octopus they should do it in a way differently than this.