User blog comment:GutsyTick/CC: Viden, the Seeress of Death/@comment-3391671-20150823163858/@comment-26044269-20150823191615

Since slows decay in potency, 100% slows don't actually immobilize someone (I think it brings them down to 110 movement speed). I don't know why Riot insists on only having up to 99% slows, when Rumble's slow can stack up to 130%. But yeah, I wanted a strong, but brief burst of crowd control tied to the passive; the 100% slow also decays over its duration, so I personally think it's justified.

Viden's playstyle is tied around vision; champions usually have 1200 vision range, hence the 1200 range on most of her abilities.

The free range on ult is there to just basically give Viden some mobility as an assassin, it is free in most regards, yes, similar to Ekko's passive on W (still don't get why that exists lol), but regardless, without it Viden would lack the very capability to gap close effectively; it's also designed to make severing bindings easier. As for Incendo and Deviare, they're just activated by pressing the R button.

Also lore is never coming out so don't ask for it.