Well, I'm looking for a cold, indifferent, anti-hero and anti-social MC. *NO Romance, Harem, Sexual Relations and NO Slice Of Life. *MC must be a loner(no friendly relationships if possible) *Revenge novels like Paradise of Gods and Demons are preferred. I don't mind if the mc isn't anti-hero at first but becomes so due to some incident(somewhere in the beginning chapters). Something like Tate no Yuusha(Shield Hero) without the romance. Also it would be good if the mc has a tragic past or suffers at some point of the story. Edit: I'm okay with novels from RR or anywhere else as well. Also I prefer a male MC
Mm, Renegade Immortal seems to fit your bill, although there *is* some romance, it isn't prevalent in the story. Death Notice seems like it too. Also, King of the Battlefield.
Reincarnator - he uses his relationships to improve humanity's condition but he goes alone 99% of the time
There's barely any romance...Wang Lin is strictly focused on his cultivation and becoming an immortal. He spends most of the time so far cultivating. He's essentially a loner.
warlock of magus world is a nice suggestion but not revenge per say however has quite bit translated and is done very well. another suggestion that fits quite well to your description would be Nidome no Yuusha it has a romance genre but the current developments in the story don't really lead to any at the moment however a great revenge story
most of the novels mentioned above has either harem or romance~ I won't say much cuz it'll be a spoiler and this is not the place for spoilers but even WMW and DD has them~ Death Notice is the best suggestion for your requirements~