Well that's a funny story. Almost everyone in TTV that knew me in early 2009 calls me "Mange," because my username was Mangekyou Itachi at the time. Then in the middle of the year I changed to Invictus, so people started calling me Invi. Then I added the Tenebrae and people still called me Invi after that, so Invi stuck.
People have called me Tene, but I'm used to people saying Invi or Mange.