So we're right back to hating the gays. Ah, gotta love Tumblr.
It's Japanese, most likely butchered, and I think it's "I hate them" and "I'll kill them."
Correct me if I'm wrong, but isn't "desu" considered a word of politeness? Kind of like saying "I hate you, sir. I would like to murder you if you wouldn't mind terribly."
Anime and manga characters often end their speech/sentence with some word or phrase. This is done to show their character or simply as a joke. You will find numerous servant type characters (maid in particular) as well as polite older or "old fashioned" characters use the "desu" ending. Rurouni Kenshin (nice and polite samurai) for example says the desu often. (The character is much more complex than that, but relevant to this discussion: his use of the word desu ALL THE TIME is meant as a example of how he is polite.)
Likewise if you have a character that is a talking cat then every single phrase it says ends with the equivalent of "meow." And "Fairy tail" made a joke about it by having a crab-man appear and everyone had expected him to end his sentences with "crab" but instead he used the name of some other animal, because they were joking with the joke by subverting it.
Now that I think about it, Mahou Sensei Negima also joked with this. There was a character that hadn't said a word in most of the series and when she started talking all her sentences ended with "pokyo" (or something like that) and the characters debated whether that was weird or just part of her being a "odd/cute character." ...Then she started accidentally using other words and people realized that she was just playing around.
Translators usually leave it out because it would sound extremely silly to non-japanese, but my point is that the "desu" bit is a anime/manga trope that really does not translate well. In this case being polite while giving out death threats is the equivalent of a dude in fedora and leather coat tipping his hat and going "my lady" because he thinks it makes him look cool.