The easiest way to obtain frenzy crystals in Monster Hunter Wilds is by fighting “frenzied” monsters. We have seen reports that some frenzied monsters drop these items while fighting; however, we collected a frenzy crystal as a reward following the successful defeat of a Frenzied Blangonga via the menu.

Our Monster Hunter Wilds Suja Textiles guide explains how to get this rare trade item you need to craft a Suja Sash.

The reason I'm confident that Lagiacrus is coming to Monster Hunter Wilds is that the brief tease showed a green-scaled monster, with plenty of underwater sound effects. Lagiacrus debuted in Monster Hunter Tri, notably featured in a hunt that made use of the game's underwater combat. Hopefully this style of hunt returns for Wilds.