The Grand Vizier gives you a sly smile.
"I can offer your man full amnesty," he says, "on the condition that he remains a ward of the Triskatani state. He may never leave and will be taken care of. How does that suit him?"
Wentar- you could not have hoped for better! No blackmailing required.
Vlad- all of this irks you. Marl is getting away with an entire life of slaving, one that you were victimized by along with countless others.
Wentar smiles at the idea of not having to use any blackmail. He also believe that, despite Marl being a slaver, he will be forced to go straight while confined on Trikistan. It's not Wentar's favorite decision but in comparison to blackmail it's better then he can hope for.
"I will inform him of your generous offer and transmit his answer to you shortly," Wentar says with a bow. "Thank you for your time."
This does greatly unsettle Vlad, as justice is not being carried out accordingly. However, his Jedi training teaches him to keep his emotions in check and stand by Wentar's decision. After all, by letting Marl go with all he has done they will have a chance to shut down many more slavers just like him.
Vlad handles things maturely, then, and Wentar lets Marl know of the Grand Vizier's offer.
Marl laughs heartily. "Full amnesty? I could not have hoped for better! I will tell you what I know of Loj'oon.
"Loj'oon is not your typical slaver; not a brutal guy. Maybe smarter. Anyway. I dunno what he did, but he got in the good graces of the Kylugo Srum somehow. Now he's big news. There's not much more to it than that. I can tell you something that may help you, though...
"Loj'oon started off his career with the Srum as a slave."