Trunda is the hottest champ, FYI.
re: Vizier buff ext acc...great question. I have him and use him in CB NM Brutal and Hard. Given the ACC requirements increase for each CB level, I have noticed he almost always extends in Hard but less often in NM. I have Vizier at 186 ACC. Good luck and do not forget to turn off his A3 when the CB is at Void affinity.
So Elenaril isn't going to be jealous of Venomage, but instead Narma. I also tried Fronzen Banshee but thge poison wasn't building up fast enough. Ultimately using Narma, Geomancer and the Vizier as my DPS in my Double Maneater, my damage has gone up 10-15M. The Vizier replaced Fahrakin the Fat. Also, with the debuff extensions, I locked out Geo's A3 so he only does damage (after I manually trigger it in Turn 1).
Anyhow, Vizier Ovelis was geat addition to my CB team.
I actually have 2, so now I am trying to decide if I am going to develop the second and maybe use him in Hydra.