What does ダークホース mean here?

Question

I am vainly trying to understand the paragraph below but I am running into some difficulties. In particular, I have a lot of difficulties to figure out exactly what is meant by ダークホース here (there is a comics publisher whose name is Dark Horse but I think it is irrelevant here). The other point is 予測した私は where I am not sure about who estimates what.

The extract:

この小説について
とあるご縁でお会いしたガガガ編集部の面々は、たいへん濃い方々でした。
彼らが求める小説は、きっととんがった内容ばかりになるじゃろう。
と広島弁で予測した私は、あえてひとりだけの作風でダークホースしようとして…
軽く失敗して横道スピンしてできたのがこの小説です。

My attempt at translating it:

About this novel.
A certain acquaintance introduced me to the publishing house GAGAGA, they were so much enthusiastic people. They wanted a story polished to perfection. With a distinct accent from Hiroshima, I explained that I tried at best to write in a unique and pleasant style and sought I might success even if at the beginning anybody has any hopes about my work. I slightly failed and sometimes wandered away from the path but here is the novel I wrote.

Here I translated ダークホース by a periphrase explaining that a “dark horse” may well be a horse that has been overlooked in a horse race but will win anyway. The image hinted by the dark horse may be reused by 横道スピン but I did not include it in the translation.

Answer 1

ダークホース itself is a well-known horse racing term, but ダークホースする is not common. Anyway, I guess this ダークホースする means exactly what you suggest ("to succeed although there was no expectation from others").

I think you have gotten some phrases wrong:

• 濃い here is a slang term meaning "unique", "eccentric", "having strong character", etc.
• とんがった is another casual expression which refers to the opposite of what you think. It's "very unique (although it may be rough around the edges)", "individualistic", "avant-garde", etc.
• 予測 is "to anticipate", you have to stick to the literal translation.
• 軽く here is "so easily" with maybe a bit sarcastic nuance. It implies "as a natural consequence", "as everyone could easily expect", etc.
• 横道スピン is a car racing term, so I don't think it's a reference to ダークホース.

So the author tried to write a novel with a very unique style, thinking that's what the editors were expecting. But he admits he simply failed, and the result was not a unique masterpiece but something only strange.