The Vex build for Mid is Luden's Tempest and Electrocute. This LoL Vex guide for Mid at Platinum+ on 13.23 includes runes, items, skill order, and counters.
Vex Counters
Vexwinslane against...
Win Rate
Matchup Rate
Aurelion Sol
535 games
1.1%
Annie
253 games
0.5%
Galio
286 games
0.6%
Pantheon
346 games
0.7%
Katarina
1669 games
3.6%
Naafiri
578 games
1.2%
Azir
1301 games
2.8%
Qiyana
455 games
1.0%
Sylas
2910 games
6.2%
Kassadin
618 games
1.3%
LeBlanc
1187 games
2.5%
Swain
Fizz
1155 games
Ahri
1875 games
4.0%
Talon
933 games
2.0%
Tristana
365 games
0.8%
Akali
2781 games
5.9%
Yone
2882 games
Jayce
854 games
1.8%
Ekko
523 games
Taliyah
Veigar
950 games
Ryze
424 games
0.9%
Vexloseslane against...
Xerath
855 games
Anivia
437 games
Twisted Fate
824 games
Orianna
3003 games
6.4%
Vel'Koz
296 games
Viktor
879 games
1.9%
Vladimir
752 games
1.6%
Syndra
2545 games
5.4%
Diana
401 games
Lux
1074 games
2.3%
Cassiopeia
415 games
Neeko
605 games
Malzahar
828 games
Ziggs
468 games
Zed
1729 games
3.7%
Yasuo
2203 games
4.7%
Zoe
529 games
Lissandra
716 games
1.5%
Akshan
547 games
Irelia
876 games