2871206
2871147

I've actually been around since 2011, actually. This is my second (heh) account.
But yeah, not the second ever. IIRC there were a few dummy/test accounts after knighty, with the first publicly accessible user being called PK or PW, something like that.

2871147
Fimfiction was made and released to the internet in 2011. This guy didn't come around until 2013.

2871099
Still, he is the second.

2541704
No, his username is 2, but he is user 128336. I tried it, too.

You came right after Knighty. I think...