Let us set a situation as below.
Player A owns and controls a unique character. Then player B takes control of that character through an effect.
Can player A now marshal another copy of that charatcter?
If yes, what would happen when player B give back that character?
Related: RR P22
xxA player cannot take control of a unique card if he
or she already controls or owns an in-play copy of
xxA player cannot bring into play or take control of
a unique card if a copy of that card is in his or her
According to above, "bring into play" and "take control" are not the same. So marshal is included in "bring into play", the answer to my first question is probably yes. Then I have no idea with the second question.
If the answer to the first question is no, that means marshal is also considered as "take control"?