If I remember correctly there was a cutscene in 1.0, where the MC was seeing a group of garleans that were like mindcontrolling some lalafells I think and telling them to go against the eikons, maybe SE is finally using that plot point (it was during the first scenario of 1.0 btw) and implying that they were servants of Solus that were corrupting ppl to sic them in killing primals, afterall ascians have always said after each kill of a primal it is actually making hydaelyn weaker. Perhaps Solus' shadow is much deeper than we realize
Edit: FOUND IT!
https://www.youtube.com/watch?v=Ps-giTboFpc From 14:20 minutes
The speech of the centurion clearly doesn't sound very garleanish to me