Coming from the planet Anzat, Jerriko is an Anzati. He is typical of his species, who are tall and gaunt. They look humanoid in many ways, but whenthey catch their prey, be it human or otherwise, their true nature comes out.
Within their cheeks they have a set of prehensile probiscises, which are coiled with the cheeks. When the victime is caught, these insert tjemselves into the victim's nostrils and pierce the brain. As a result of so much 'food' in the galaxy, the Anzat live for a very long time. Jerriko himself is 1010 years old.
Dannik does not just drink the blood of his prey, though. He also consumes their 'soup', or their Luck. He has been an assassin and bounty hunter for countless years now, being paid for what he has to do to live. He is quite unique, so his prices are very high. None of his employers have questioned his prices, bar his first. But since that man had his 'soup' drunk by Jerriko, none have dared to complain. His main employer is Jabba the Hutt, and he has consumed many failed assassins who have not been dropped into the rancor pit.
During the time when he had no jobs, he felt himself drawn to Tatooine, and to Mos Eisley in particular. The mixture of killers and other beings called to him. He just had to taste the Luck there. It was in the Cantina that Jerriko smelled the sweetest of soups, Kenobi's. Ben Kenobi and Luke entered and dealt with Evazen and Ponda Baba when they threatened the young Jedi. During this altercation, Jerriko realised that he would never be able to taste Ben's soup, as he was a Jedi Master and could shield himself from the Anzati. But then he smelled Han Solo, and knew he had to have him. Jabba's contract on Solo said dead or alive, and Jerriko intended to deliver him dead, empty of Luck. But Solo left Tatooine in a hail of stormtrooper fire, and Jerriko knew he had missed his chance. Or had he?
Dannik knew that Solo would end up in Jabba's palace sooner or later, and so he set in motion his plan to infiltrate the slug's desert palace. He would wait in the shadows, and pounce when the moment was right.