You don’t have to tribute vision heroes to bring increase from the back row to the front row. It can be any hero. In terms of the roll he fills he allows vyon to be summoned. Essentially when you have a faris you discard a monster, Mali if you have it or dynatag but if you discard shadowmist don’t activate it’s gy eff if you have a way to special it. If you do then add liquid. From their you activate faris effect to set increase in the spell trap zone. You then special increase by tributing any of your heroes on your field. This allows you to special any level 4 or lower vision hero so you bring out vyon. With vyon special summoned you send shadowmist if you haven’t already or mali. From their with mali you can banish a hero that’s served it purpose to add poly. The just fusion and link away. If you remove increase your just have a monster that can special its self and that’s it. Nothing crazy useful.