The Viktor build for Mid is Rabadon's Deathcap, Lich Bane, and Luden's Companion. This LoL Viktor guide for Mid at Platinum+ on 14.3 includes runes, items, skill order, and counters.
Viktor Counters
51.6%
(-1.0%)
52.1%
(-1.3%)
3.9%
(+0.2%)
1.5%
(+0.1%)
922
(+2)