These three unnamed Leviathans acted as guards at SucroCorp.
These three Leviathans were assigned to guard SucroCorp after it was taken over by Dick Roman. When the Winchesters attacked, they were drawn out of the building by the Impala crashing through the front gate and giant glass sign.
Emerging from the building, the Leviathans opened fire on the Impala, but it was driven by Meg who, as a demon, was unharmed by their bullets with the distraction allowing Sam, Dean and Castiel to sneak in undetected. Meg quickly splashed all three Leviathans with borax and then decapitated them with a machete. With the guards defeated, Meg departed but was captured by demons working for Crowley moments later.