Hal Jordan's enemies: Honnu
Like most of the Lost Lanterns, Hannu maintained a grudge against Hal for his acts while under the influence of Parallax. During the Sinestro Corps War, the Lost Lanterns were sent to Qward to rescue Kyle Rayner from the Sinestro Corps. The Lanterns soon got lost while searching the planets expansive underground labyrinths. Turning blindly into a new chamber, they suddenly discovered that the Sinestro Corps was resurrecting their own "Guardian" the Anti-Monitor, and outfitting him in Sinestro Corps-emblazoned armor to amplify his anti-matter energy. The Anti-Monitor turned his massive power on the Lanterns' leader Ke'Haan and vaporized him down to the bone. They Lanterns were stunned and it was only the quick thinking of Hannu that saved them all from a similar fate. With grim determination Hannu told them all to "cover [their] eyes, it's gonna get bright in here", and unleashed a massive blast that staggered the Anti-Monitor and brought down the entire chamber, burying the villain momentarily, and allowing the Lanterns to escape with the aid of Hal .
The war moved to Earth where Guy Gardner was intercepted by a squadron of Sinestro soldiers . Alone against dozens of enemies, Guy arrogantly challenged them all, including their leader, Horku. Horku was a Sinestro soldier of the same race as Hannu. Horku was unaware of the Guardians' new law which authorized lethal force, and dismissed Guy's tough talk as an "empty threat". Horku soon learned of this new law when Hannu arrived at the head of the entire Corps and surprised his villainous counterpart from behind. Stating "empty threats? That was yesterday", Hannu punched directly through Horku's back, his ring hand exploding through Horku's chest, killing the Sinestro soldier instantly.
Led by Sinestro himself, half of the Sinestro Corps descended on Coast City to level Hal 's hometown and turn it into a mass graveyard that would endure as a monument to the power of fear. Only Hal and Kyle stood alone to defend the city against legions of enemies. Both Lanterns readied themselves for battle when they were contacted by Hannu who learned of the incoming attack. Despite their differences, Hannu recognized that stood Hal with them on Qward. The stoic Lantern lead an army of Lanterns to "return the favor" tipping the balance and saving Coast City from destruction.
Following the war, Hannu demonstrated a more thoughtful side not seen in the massive warrior. It was Hannu who recognized the pain his fellow Lost Lantern Laira endured over the loss of Ke'Haan. When Laira murdered the Sinestro soldier Amon Sur, Hannu reluctantly acknowledged that her actions were murder born of revenge, and not a just killing in the line of duty. He has also forgiven Jordan for his crimes while possessed by Parallax, and apologized when the Lost Lanterns failed to secure Amon Sur's yellow power ring. When Laira was expelled from the Corps for her crimes, Hannu piloted her back to her home world. Their ship was intercepted by a red ring of power, which sensed Laira's burning rage against the Sinestro Corps and inducted her into the Red Lantern Corps. Hannu was blasted from the ship and gravely injured, but was rescued by his fellow Lost Lanterns Graf Toren and Tomar-Tu. He sadly reported the news of Laira's conversion to his fellow colleagues. Presumably he has recovered from his injuries and resumed his duties as a Green Lantern.