Aru Akise

Aru Akise is an albino angel who seems to appear out of nowhere, then falls in love with a whiny brown haired kid and gets decapitated.

Highly original.

He wanted to become a detective, but not an annoying Tumblr detective like that Superwholock guy.

Why half the Mirai Nikki fans hate him
Short answer: Yandere fans are evil.

He keeps talking all funny
""Something something prognosticative something something cavalcade something""

- Aru Akise, being smug

He's under the impression he's more percipient than you. How conceited. Anyone with an IQ above room temperature knows that roughly 32.33 (repeating of course) percent of what he articulates is nonsensical gobbledegook that doesn't resemble any words in the average human's lexicon.

He is a haughty mountebank and deserves nothing but to be defenestrated from the apex of Sakurami Tower.

He's just there to appease yaoi fangirls
By including a character that isn't straight, Sakae Esuno is pandering. Any diversity in an anime is pandering. Acknowledging the existence of gay people is pandering.

He's not Yuno
Some people only watch Future Diary for Yuno. How pathetic. How... Sad...

He can walk around with his head cut off
The show never even shows his body fall over, which means he could have survived being decapitated after all.