I'm playing in a solo game where my character was part of a mercenary group of assassins and was betrayed and left for dead.
Now I'm trying to pull a "Count of Monte Cristo" style revenge but I'm struggling to figure out how to go from nothing (besides being a highly skilled assassin) to being a criminal mastermind so I can enact my revenge.
It is a low-powered game so my character is mostly mundane, just highly skilled in melee and with disguises.
I've identified three things that I need:
1) Money
2) Minions
3) Information on my enemy
And that is roughly the order that I am looking to develop. For 1) I'm thinking about using his mastery of disguise to blackmail/extort rich people. I was thinking about avoiding pressing on other criminals and instead focusing on the soft wealthy elite. Go in, grab a bunch of money from some rich industrialist, then kill him and move on to the next.
For minions I was thinking about just taking over street gangs. Just go in, kill their leader, shout "Anyone else?" and then shower them with money from 1) and build an empire that way..
Once I've got 1 and 2 I can put out contracts to try and entice my old mercenary group from hiding.
That's my plan but I'm really excited to hear other people's ideas as I've never done a sandbox villain game before.

4) Skills to acquire and manage the above.

Seems to me a master of disguise and accomplished assassin could just find a global criminal organization with a shadowy figurehead and perform a quick takeover, thus achieving number one and two in short order.
So, who wants to be the next Dread Pirate Roberts?

Can we narrow the variables a bit? As in, are we talking low or no magic, what kind of tech level, and what kind of revenge? Are we overthrowing a kingdom or stealing someone's house and seducing their wife? Does the character have any moral code or are we talking sociopath spitweasel?

In the most general/generic sense...if it benefits you to kill someone, kill them. Need a house? Find someone who lives alone: your house now (you are "looking after it whilst [owner] is in the country"). Use their capital, get some pigs, insert yourself not only in the inconvienient-body-disappearing trade but sic rival gangs on each other with carefully-implicating murders then sweep in with whoever's mob now owes you favours/you can persuade, and take twice the territory(/win it for your new boss). Offer good terms to neighbouring crime lords and accord their grown children the honour of serving in your bodyguard (treat them well and convince them their parents gave them up to this, that you are their family now - test loyalty by discussing fake plans and seeing who bites, making the mole and the vassal brutal examples). Personally kill the leaders of those that will not join you until they get the message. Gatsby yourself into high society as soon as you can float the charade, gather intelligence until your desired means of revenge is plausible, avenge self, get old and comfortable until someone inevitably stabs you.

If your character is a former assassin, I would think Hit Man would be the way to make money. Rich people often need thorns removing from their sides.

Minions, like everyone else, seek wealth and status. Pay well, and be That Guy or That Organisation that everyone wants to associate with. Unfortunately, the more status you have, the more likely your enemies are to find you - unless for some reason you're unrecognisable. However, even the smallest outfits can attract minions.

Mutiny tends to be a double-edged sword that you may die by if you live by it. Take overs lead to more take overs. Best to avoid putting ideas like that into your minions' heads. (Or your GM's head).

Part of your empire could be legit, with employees rather than minions. A private eye, bounty hunter or repo business could legally dig up information on your enemies. Of course, if all their marks wind up dead, someone might smell a rat...
This message was last edited by the user at 04:07, Mon 15 July 2019.

If your character was betrayed by this group, are there other individuals/groups that have been similarly betrayed by them?  That could be a good place to start...join forces with someone else with the same axe to grind.  Utilize their resources to get information (this also leaves them as the more likely target if your ex-comrades realize someone's asking the wrong questions or getting too close.)

I agree that hiring out as a hitman is likely a better way to make money...people with the money and morals to be good blackmail fodder are also likely to be willing to take extreme measures to avoid being blackmailed...let someone else try and blackmail these people, you're better off being the 'extreme measures'. (This might also be a good way to ingratiate yourself with some shadowy groups...if you're saving their friends--or even boss--from being compromised, that gets your foot in the door on friendly terms.)
This message was last edited by the user at 22:35, Wed 17 July 2019.

I agree that Hit Man is a better route than Blackmailer, especially if you plan on killing your victims afterward- too much of that will draw attention. If Lord Willoughby is looking anxious and then turns up dead, weeks after Lord Chauncey and Lady Harton-Smythe met the same fate, people are going to notice and gossip. Blackmail tends to work best if you go for affordable amounts and then vanish.

If you're that good at disguise, Con Artist is another route to go. Disguise yourself as Lord Willoughby, get to his secret stash and grab it. Preferably do all this far away from the home base of your former organization.

One thing to consider is if they've done this to you, they've probably done it to others. It might be worth trying to find them- they aren't necessarily allies ("The enemy of my enemy is my enemy's enemy. No more. No less"- The Seventy Maxims of Maximally Effective Mercenaries) but they may have information for you.

When all else fails, do what the CIA did when they needed money fast - Drugs and guns. Everyone from the street-level hood with a record to the warlords of Africa need weapons, and everybody knows somebody with a drug habit.

Pretty much every powerful criminal organization uses those two bits as the foundation of their income, so why should yours be any different?

I agree with Nowhere Man on where to get the money, but not how. Governments use all kinds of black operations. That should be your victim pool.

Why put all the work into running guns and drugs when you can just steal somebody else's stash. CIA is doing another Fast and Furious with Mexico? You replace the driver of the truck. Blackwater has a new contract to raid a stash of gold in Afghanistan? You replace the squad leader. A European government is secretly paying some big tech company for some hush hush upgrades to a facility by sending a courier with bearer bonds? You intercept the courier.

Looking for minions? Hit up a bar in Cuba where all the old spooks hang out talking shop, reliving the glory days, and trying to get a whiff of what is going on now days. Some of them would be happy to get back in the game and may have some valuable resources as well as contacts to help get you headed in the right direction.

Thanks everyone! this was a lot of help and gave me a lot to think about!