There is something called "On and Off" it's either a switch, a button, a vocal order or even more modern a mental order. And knowing how retard yukkuris can be, i be she considered that the act of "believe it to be active" would be enough.
Sorry Yukkuris but you aren't Orkz, and even they need something a bit more, "worked up" before their "belief" psychic power kicks in to enchance it.
Becoming Fearless =/= making red be 3 times faster or orange be 10 more explosive out of belief.
Hell one may say that they are fearless even alone until abuse triggers the fear, even in groups, if you smack them around they may still fight back and shit, only when you start ripping apart body parts they break up.
No worries, they lack psychic capacity and clearly lack the basic ability of doing averagely developed constructions like the Orkz.
So if anything they'll be a parody of the orkz in the "a race dependant of belief to "makes thing reals" " part, but of course, it really doesn't work with yukkuris outside of their few organs.
Confidence in numbers - Yukkuri Leadership can be Modified by the numbers of yukkuris in the unit , if there are over 10 yukkuris in the herd they count as fearless,
Take it easy - at the start of the turn every yukkuri unit must pass a unmodified leadership test , if they fail they count as taking it easy and may not move this turn
Soluable - all water counts as impassable terrain
our easy place - if a yukkuri unit is at an objective they may not move off the objective.
WHY WOULD YOU DO THAT !?!?! - yukkuris count as having hatred against all other races and all other races count as having hatred of yukkuris.
Not to stir things up but would Africans qualify for "a race dependant of belief to "makes thing reals"? They're always talking about "keeping it real" and if a member of their race does inappropriate things they say "you n*gg*z ain't real" as if they believe they can cause aforementioned members to phase out of existence simply by stating they are not in fact real.