Mid Lane Kench, aka M1 Abrams Build

Kench is a tank. Any build that succeeds with him will be tanky. Why? Because he has one of the strongest ults in the game.
Passive: Basic attacks and damaging abilities deal an additional 0 (20 + 4/6/8% of Tahm Kench's bonus health) magic damage.
This translates to:
8% of health is added directly to the damage of each and everything you do.
Lets take a look at a few AP items:
- 500 life / 100 AP - 110 damage to Q ; 2% max health + 40 damage to single target W ; 100 damage to AOE W ; 40 damage to auto attacks
- 400 life / 100 AP - 102 damage to Q ; 2% + 32 W Devour ; 92 W regurgitate ; 32 damage auto attacks
- 300 life / 80 AP - 80 damage to Q ; 1.6% + 24 W Devour ; 72 W regurgitate ; 24 damage auto attacks
With those three items alone, at max level, your skills will do the following: Q = 260 + 110 + 102 + 80 = 552 damage W Devour = 32% + 2% + 2% + 1.6% + 40 + 32 + 24 = 37.6% max health + 96 damage W Regurgitate = 300 + 100 + 92 + 72 = 564 AOE damage Auto Attack = 40 + 32 + 24 = 96 magic damage
So if you W a minion, Q the champ, then spit a minion at the champ, you just did 1116 damage to that champion with 3 items and no masteries.
Ultimately, I think mid-lane kench will be built like a sustain tank. Those 3 items +
+
+
. That would give you incredible sustain from Visage + WotA + E late game, and early game your Q-W-Auto-Attack trading will beat most mid-laners in 1v1s. Tremendous lane bully potential detected. Building rod first will counter his mana issues since his spells don't go up in mana cost as they are leveled. The additional 400 health from Visage will add roughly 32 damage to everything you do, and the 80 AP from WotA will add 56 to Q, 1.6% max to W devour, and 48 to W regurgitate.