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can a warboss be in a mob of trukk boyz??? and can a big gun have no slaver??
If there are only 9 trukk boyz I'm pretty sure he can mount up with them (though he will have to start up unmounted). However I'm not 100% sure about this so you'll have to get some more opinions from vet players.
As for the slaver and the big guns, no he is not necessary. Neither is a mek, you can easily have a big gun team that has nothing but grots. Although adding meks or slavers add to the potential survivability of the unit.
Gargrimz Green Deff
W:10 D:4 L:5
The Warboss is an IC, which means he can join other units. Just note however, that, if the Trukk Boyz mob already has 10 boyz, then if the Warboss joins them they will not be able to ride in the trukk. So if you want to do this you'll want to put only 9 boyz (or 8 boyz and a nob) in the Trukk boy unit, then have the Warboss join them to make 10 models in the trukk.
Monkey's Killer Kan WiP (Updated 4/29)
A warboss must be part of the unit to be transported in the trukk. Also if the units model count (including grots and squigs) is over 10 then they cannot ride in the trukk, but they could if no more then 20 ride in a battlewagon or battle fortress. Big guns can have a slaver for extra points but it is optional. Hope that helped.