User blog comment:Jopjopjop/Volume 20 Spoilers/@comment-3965848-20150720134401

What would be awesome is if Vali absorbed half the power of Issei's new form, Issei's power remains the same since half of infinity = still infinity.

by that logic, Vali's power would also be infinity and unaffected by Rizevim's ability, if only he also had the body to sustain it like Issei.