For example, Ren the Ringwraith is in Barad-dûr. I can put an Orc character into play in this same site, considering that I will do it in a separate company what is going to move to another site in my Movement/Hazard phase?
ME:LE rulesbook says:
ME:LE, Standard rules, Companies, Limitations on Company Composition, p. 21
Unless at a Darkhaven, a Ringwraith may not be in a company with other characters.
But ME:LE rulesbook also says:
ME:LE, Standard rules, Bringing characters into play, p. 58
To play a character card, you must have enough general influence or direct influence available to control the character into play. In addition, you must meet both of the following requirements:
· If the character is not an agent, you may only play him at his home site at any Darkhaven site. If the character is an agent, you may only play him at his home site.
· If your Ringwraith is in play, your Ringwraith (or a character with enough direct influence to control the character to be played) must be at the site at which the character is to be played.
ME:LE, Standard rules, Bringing characters into play, p. 20
When you play a character, you may place him into a company already at his arrival site or he may become a new company (consisting of one character). In the second case, you must place the arrival site card next to the character played. If the appropriate site is not available, you may not play the character.
CoE #67 says:
You may use one site card to represent multiple companies during the Organization Phase, but not during any other phase.
And CRF says:
CRF, Organization phase, Playing characters:
If you play a Ringwraith at a non-Darkhaven site where there is one of your non-Ringwraith companies, one of the companies must move that turn. If both companies are still there at the end of the movement/hazard phase, discard the non-Ringwraith company.