The entity of greed that Larfleeze keeps chained within his Orange Lantern is a snake-like being called Ophidian the Tempter. It was the first being to consume more than it needed, and thus became the first example of avarice in the history of the universe. It speaks to and wields its corrupting influence over whoever possesses the Lantern. When Krona dispatched Hector Hammond to find Larfleeze and the Lantern, Hammond consumed the Lantern and became the host of Ophidian in much the same way as Hal Jordan had once been the host of Parallax.
After joining Krona, Ophidian used its powers to pinpoint the location of the Butcher, the entity of rage that Atrocitus was on the search for. Once Krona had collected all the entities, he launched an attack on Oa, where Ophidian and its fellow entities each possessed a Guardian. After Krona was killed by Hal Jordan, Ophidian was released from his hold and is currently roaming at large in the universe.
In the earliest times of Earth, Ophidian was created when a serpent ate more than it needed. This serpent eventually became Ophidian, the emotional entity of greed. A long time after that, Larfleeze sealed Ophidian within his power battery using a procedure which Larfleeze described to Hal Jordan as "a bit tricky".
Prelude to Blackest Night
When Jordan took the Orange Power Battery from Larfleeze during the Agent Orange saga, the greed entity spoke to him in an attempt to make Hal give in to his greed. However, Larfleeze quickly stole it back before that could happen.
Night and Day
In Green Lantern vol. 5 #52, Sinestro witnessed the creation of Ophidian when he bonded with the entity of life.
In Green Lantern vol. 5 #54, Atrocitus used the blood of bones to see where the different entities are and the orange lantern symbol is over Minnesota.
In Green Lantern vol. 5 #56, Hal Jordan came to Larfleeze in order to ask him how he managed to seal Ophidian inside the orange lantern. Before he could get a straight answer, Hector Hammond attacked, seeking the entity of greed. After a quick skirmish, Hector simply ate the lantern. This caused Ophidian to possess Hector Hammond and take over his body, stating that it was time to get even with Larfleeze. He then helped Krona take the rest of the entities, including the Butcher that Atrocitus caught earlier.