So, in the event that he is approached by one, or both, of the so called "big baddies," it would not remain a matter of volition that he joins one of them or not? The way you say this makes it sound like
1) He literally has to join the tribe the tribe he is approached by (or else?)
2) There is no possible reason in the world for which he would not want to join one of these "big baddies"
The assumption here is that he has either put forth an application to be recruited, or has otherwise been contacted by, or put in contact with, the leaders of these 2 tribes in a way such that would encourage him to join the tribe.
Considering all possibilities, suppose he were approached in simultaneity by these "big baddies," and is simply unable to come up with a good reason to decide in any particular way. In his case, perhaps such a ratiocination would be: "Well, by position, @Night is clearly a better choice. However, I strongly oppose x in @Night and very much like the fact that Norse does x in the opposite way" or something to this effect. The point, primarily, is that one cannot make such an assertion without having a complete perspective, which truly only turtle has, for him, that is. Furtherre, it is entirely within his powers to decline such an invitation, and, if this is not the case, I will require reasoning for such a claim (as everyone ought to).