RiskTheRiolu

Name: Basque
Interesting. I assume it's a different language name. I like those. 10/10
Age: Estimated late 20's or early 30's. Nobody actually knows.
Okay, does he keep it to himself? Well, he must. Sometimes I see this as a lazy excuse to not come up with an age for an OC, but I wing judge to much for that. 9/10
Species: Vaporeon
It's a common Pokémon to see being used, but I can't judge to much for that. 8/10
Personality: Extremely cold and introverted. He is not quick to make friends with anyone, and, to him, actions speak far louder than words. He is also very purpose driven- which gives him a black-and-white view of the world.
Wow. This is a rather rare personality. I mean, I see introverted personalities a lot, but never as deep as this one. 10/10
Likes: Finding overconfident Pokemon and taking them down, surviving, and the color crimson.
Interesting. Definitely not seen often. 10/10
Dislikes: The smell and sight of blood. Also, anyone that attempts to harm someone he considers a friend.
I find it surprising that he doesn't like the smell and sight of blood, seeming as it is something he probably comes across a lot. 7/10
Backstory: I will not say everything for fear of spoilers, but I will say that his genes are quite unstable after being plucked from the wild and experimented on by a group of underground scientists in Kalos, in an attempt to create a self-sustainable Pokemon. This did give him an enzyme that would allow him to sustain himself, but at the cost of a very, very fast metabolism.
Basque was helped by his Trainer to manipulate every part of himself as free water, allowing for him to merge with water, as well as become it, himself, at will. However, Basque found a way to incapacitate his enemies with this technique, by literally enveloping them in water, forcing them to where his stomach would be, and liquefying them with a special enzyme found in his stomach. Although this "water-stomach" could be used to hold a Pokemon to keep them safe from harm, Basque would never willingly let himself be used in this way.

However, this fantastic ability comes at the cost of using his moves, among other things, while he is made of water. Also, due to this enzyme in his stomach, Basque's body is only able to use meat for food. This, coupled with an absurdly-high metabolism, makes life quite challenging at times, especially since his throat doesn't work quite right due to having a fisherman's hook ripped out of it.
Wow. This shows his struggles and advantages in life evenly and well, and it's very deep. I love it! 11/10
Moveset: Muddy Water, Rest, Acid Armor, Ice Beam.
Nice moves. 10/10
Other: https://www.wattpad.com/286053003-risk%27s-story-guide-basque-the-vaporeon
I can't wait to know more! 10/10

Overall grade: 85/90
This is probably the best OC I've rated so far. I love how deep the backstory and personality goes.