Ok, so I have an idea for a character based off of Kled from League of Legends, though specifically his skin 'Count Kledula'. I'm thinking a fighter, maybe some blood hunter? Using rock gnome as race. Seen as he has a mount, Skarl (any suggestions on what creature he is from the picture below), cavalier fighter seems good (Though I don't have it on here). Should I choose blood hunter first, or fighter? Should I even go BH? 

Here's the referance: 

Link to his bio: https://na.leagueoflegends.com/en-us/champions/kled/

And his video/spotlight: https://www.youtube.com/watch?v=Pz145kVa-4w

If you really want to have a mount, paladin might be best for find steed. Mounts tend to die quickly, and that way you can re-summon them easily. Cavaliers are fun (I’m playing one right now) but their mount related bonuses are basically just ribbon abilities. It’s nice for them if they have a mount, but they work perfectly well without one. 
Normally, I say mounted combatant is a bad feat, but for a gnome, it might work. The problem is largely size, since a medium PC needs a large mount, which is hard to take indoors. Your mount will be medium size, so you could possibly take it into most dungeons, which makes it more useful, and therefore makes mounted combatant more viable. Although, you won’t get the benefit of the first ability, since most creatures won’t be smaller than your mount. 
I realize you didn’t ask about that, but it seemed like a natural idea to discuss. 

Reading the bio, it seems like he’s a soldier, and really any melee class can be flavored that way. 

So, what do you think of blood hunter? Is that a no go? 

And, since I don't have cavalier on here, do you think renegade works? One of his abilities is that he has a pistol... 

I haven’t really looked at either of those classes or played them to be able to say (I really only stick to WoTC published stuff). I would say, if your DM allows firearms, there are going to be ways to get proficiency in them without taking a class for it. 
Looking at his abilities, have you considered paladin? That gives you a mount you can summon. There’s feats, like magic initiate you could use to pick up a spell like lightning lure, which looks like one of his abilities (or just use compelled duel) A big damage attack is like a smite. 
The four attacks things you’re only going to get with fighter, but otherwise, pally, maybe conquest, could really fit. 
Sorry I didn’t think of that at first. 

This might be an odd combination, but have you considered a multiclass between Cavalier Fighter and Shepherd Druid? You can quite literally summon your mount, even adapt it to your environment, the Cavalier Subclass gives you Animal Handling, if you so choose. Last but not least you could flavor Thornwhip as the Beartrap on a Rope, including the pullback part.

The Bear or Hawk Spirit Totem should provide decent synergy. Only hard decision would be where to split the multiclass imho. If you want to go full Kled and "Chaaaarge", you might want lvl 15 Fighter. If you want your summoned mount to be beefier, you want to go for Druid lvl 6 and likely use the Bear aspect.

Cheers :)

Thanks. That's really smart.