I'm more than sure that you've right   - after some research  it's only one Legendary account with 2200+ posts 1300+ activity and 1000+ merits, which was created in February 2013

below is a piece of the full list (scraped in last days of april) of Legendaries registered in February 2013 sorted by the number of posts.
If OP gave real data - there is no doubt about what account it is about ...