I've never played SWTOR so I wouldn't know. That said, the Cartel tried going where the money is and where it could go unnoticed or at least undisturbed.
Kessel is an obvious place simply because the Spice trade. We control the Spice, we control a huge, intragalactic revenue source. It's noted for being where they send prisoners and criminals, so it'd be simple enough to move on in. I'm doing so with Tenloss soon with a privatized prison company to control the labor on the asteroid. If the Cartel would like to join, you're more than welcome.
Tatooine is a great place for two reasons: First, the planet is a backwater world and a haven for smugglers, bounty hunters, and other less reputable sorts of individuals. Second, Gajjulla already owns a palace there. There's not much law on Tatooine and even when the law is broken, those in charge know that when Hutts are involved, it's better to just turn a blind eye to the matter unless it's a major occurance. Long and short, we can base our operations, to an extent, from the planet. Later on, a new planet may be better suited to a role, but for now Tatooine serves well enough.
Manaan we really can't pass up on. To start with, they're gonna need to rebuild. The damage done from the fighting will need to be repaired and structures rebuilt. Even standing buildings and such will need repairs and inspections. That means we can come in and set up shop through simple things like construction companies and various, niche-role specialty fields like electrical work, sewer work, etc. The payoff? Well, for starters we make a profit off the work done and establish our companies and workers on planet as a long term source of revenue. Afterwards, it lets us get situated within the Kolto market. The Selkath own all the Kolto and are not tolerant of outsiders taking the stuff, but that doesn't mean we can't ship it out for them or just sneak some here and there. Will it be a constant source? Not unless we find a way to divert the Kolto to us somehow or get into the harvesting of the stuff entirely. But what we will get we'll get at a lower cost to us and can sell what we don't need on the market for cheaper rates.
I'd intended to go into more detail like this, but work's been killing me and I did the initial post from my phone.
@[member="Gajjulla the Hutt"]
