User blog comment:Legionwrex/I figured out how many Reapers there are!/@comment-5271559-20120803143559/@comment-2250460-20120803175805

The Leviathan is not the same as the Leviathan of Dis. The LoD was destroyed and acted like the Derelict Reaper, where as the Leviathan is fully functional.

It is not confirmed that Harbinger is the oldest and strongest, the codex, which is written by people only speculating, state that it is believed Harbinger is the oldest.