Is Urianger going to betray us?

[CyrilLucifer]

I don't think he will.

If anything, Elidibus gave him the Auracite because Elidibus was the one who wanted to get rid of the problems on his side (that little clique we saw at the end of 2.0, the Watery Trigon; Lahabrea, Nabriales, Pashtarot). They were definitely acting up.

A quote, from 2.1:
"Perhaps Lahabrea may yet learn from his mistakes."
And when Lahabrea doesn't learn, that's when you get the frustrated Elidibus from 2.55, who gives Urianger the Auracite.

I really do think Elidibus intended for you to kill Lahabrea with it, not necessarily Igeyorhm. I think he believed Igeyorhm could have been reeled in, so to speak, given she had more of a passive personality than Nabriales and Lahabrea, if the more direct and brash members of her little group were gone.

But we killed Igeyorhm instead, since she tried to escape first.

The thing about Elidibus is that we don't know his methods. A lot of people seem to be projecting the methods of the brash, more impatient trigon onto him when he has clearly condemned them (and likely actively eliminated one of them). We know his end goal, but we don't know the reasons why or how he intends to reach them.