This is Captain Euler: The roundest, most fear-Sum Pi-rate of all the 3.14 seas! He was born on March 14, 1592, from a noble line of knights that all served the Round Table. However, his overbearing father, Sir Cumference made him want to roll away from knighthood. And so, he did. He took all the coins he's collected over the years (which were quite a lot, as he refused to use any forms of currency that weren't circular), donned a cheap hat that he found at Target (get it, cuz the logo is a circle), and rowed off to pursue a life of Add-venture. 

Other Info: I decided to make this character in honor of Pi Day, which I know was a month ago but still. Just in case you didn't notice, the bottom half of his body is literally made of pi. I'm not sorry. I'm also not sorry for all the puns in the description.