After several ideas from members of StarGateWars Forum I have made a decision to write up all ideas and put them into one.
Enslavement would be a tip of attack, which would enslave a person and automatically protect it with half of the defense the master has. While the master has the person enslaved, he would get from 1-5% of their naqudah per day. The maximum number of slavers would be calculated on the master income “bigger your income is less slavers you can have” however the minimum number of slavers you could have would be 2 and maximum 6.
While I have suggested a new tip of units I'm reclaiming that input and would like to suggest that Enslavement units would be the mercenariness which has NO value in the game at this time. Attack mercenariness would attack the target, Defense mercenariness would defend the target and the master, while the untrained mercenariness steal wont have any action.
If the master has successfully enslave a person, the slave would get an option visible on the command page to free him self, however that option would open after the 48 hours from the time the slave has been slaved, also the master has the option to abandon the slaver. I would also suggest that the slave after clicking the “free him self” button he would get 48 hours to gather army of untrained mercenariness which is suppose to be 10% of attack mercenariness his master has.
When Sleipnir wrote “And how do you plan to make it work when trying to enslave someone who is already a slave? Or someone who has his own slaves? This suggestion needs a lot of details to be worked out.” he really gave me some thinking and here is the complete answer: I would suggest a system which would work as the planet one, if someone is already slaved and someone let us say Spirit would like to slave him under his command he would have to fight with the master of the slave and if he would succeed the slave would be free for 24 hours so his current master could take him back by attacking Spirit. If the Spirit has succeed in the retake of the slave the slave will not be able to be retaken by other person for a minimum of 15 days.
The naming of the functions for human, asgard, goa’uld and replicator is up to you and admin but I really like this idea given by someone called An_Hur.
maybe human and asgard could have protectorate
Goauld would have enslavement
replicator may have assimilation
on the end it would all work the same.
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The Tauri was one salve but with time they overcome their master, so have many world.
so maybe add a time factor to the slaving thing...
The first day of enslavement, something like 50% income goes to the new master then slowly diminish toward 1%. (-5% per day, down to 10% then 1% a day)
above 25% the master could set free their salve but the slave couldn't escape without being freed by someone else.
under 25% the slave could initiate a revolution that would last for x days and cost naq and UU but it would automaticaly work...
the master must put UU in 'defence' that would equal or be greather than the attack forces of the slave world or he automatically lose the slave world. The stronger the slave become, the harder it is to keep it. And more slave you have heavyer is the burden to keep them.
You could have a system where taking someone as a slave costs you a certain amount of naq each turn depending on the units the slave has. Miners/Lifers would cost the most, then defenders / attackers / spies, lastly would be UU. This way an inactive high earner is still going to cost a lot to keep.
You would then need an insurrection option for the slave, some sort of calculation that when met would allow them to be free.
Only problem I can see is how do you stop someone from re-enslaving you after you manage to successfully free yourself.
I now there are steal questions but I hope I can answer all of them, also this update visible here at:
http://herebegames.com/StarGateWars/vie ... hp?t=17059 will add some good protection for a master not to slave a bunch of inactive s.
Connection/Spirit/mystery a.k.a Mitja
, up to +100% income and up... mabye? 
that would be your limit, as sleip suggested with the slaved people seeing it as an op for escape, also mabye the more people slaved reduce your strength when fighting them (making it easier to escape) not a linear division... some log function perhaps? Or mabye have your power being the limits to your slaving rather than the income, and just basically having the more people who you have slaved reducing your power against them more... 
