Hello this is my first guide it's small and simple here is all you need in runes masteries and item's for Tahm Kench you can change to ignite if you want but i prefer tp

Magic pen for the extra dmg on your skill's
Armor and mr for the extra tankines
AAAnd the ap for more dmg but can be replayced by movement speed depending on playstyle

Pros
Save his allies from danger
Very Good Sustain
Hard to kill
Good lane presence
Scales well
Can engage with a teamate for a good combo
He can disengage very well
Cons
small range can't do well vs high range champ's like cait
Has no proper escape
Hard to master
Ult channeling can be disrupted by a single aa
No hard/aoe cc need's time to stun someone

Flash - a must for escape/secure a kill/ save a teamate/peel in tf .
Teleport - the best spell he can use for top lane since he got sustain and he will stay all day long on lane grab a flask and stay there back and tp either for gank or to be back in lane with your item's without losing creeps(gold,exp)
Ignite - A great spell but a very agressive one but could be usefull vs swain/volibear/mundo and high hp reg reliable champion's

An Acquired Taste
By damaging enemy champions with basic attacks and abilities, Tahm Kench builds stacks of An Acquired Taste on them. At three stacks, he can use Devour on an enemy champion.

Tongue Lash
Cost: 50 Mana
Range: 800
Tahm Kench lashes out with his tongue, damaging and slowing the first unit hit. This ability gains a stun after three stacks of An Acquired Taste.
Damage the first enemy hit for 80/115/150/185/220 (+70% Ability Power) magic damage and slow them by 30/40/50/60/70% for 2s. Champions with 3 stacks of An Acquired Taste will additionally be stunned for 1.5s.Activate Devour while your tongue is in midair to devour monsters/minions from a distance.


Devour
Cost: 90 Mana
Range: 250
Tahm Kench devours a target, dealing a percentage of their maximum health as magic damage. He can spit devoured minions and monsters out as a skillshot that deals magic damage in an area upon impact.
Devour a target for 4/4.5/5/5.5/6s (half that for enemy champions.) Enemies are dealt 20/23/26/29/32% (+[2% Ability Power]%) of their maximum health as magic damage (maximum of 400/450/500/550/600 against neutral monsters).
Enemy Champions: Requires 3 stacks of An Acquired Taste to be devoured. While holding an enemy champion, Tahm Kench is slowed by 95%.
Allied Champions: While holding an allied champion, Tahm Kench gains 30/35/40/45/50% movement speed toward enemy champions (halved when not moving toward enemy champions).
Minions and Monsters: Reactivate to spit them, dealing 100/150/200/250/300 (+60% Ability Power) magic damage to targets hit.

Thick Skin
Cost: 50 Mana
Range: Self
Tahm Kench turns incoming damage into gray health. As gray health decays, Tahm Kench is healed for a percentage of the gray health amount. When activated, this ability turns all gray health into a shield.
Passive: Damage taken while this ability is not cooling down is converted to gray health. If allowed to decay, 20/26/32/38/44% of gray health will turn back into health.
Active: Convert all of your gray health into a shield that lasts 6 seconds, but falls off gradually over that time.


Devour
Cost: 100 Mana
Range: 4000/5000/6000
Tahm Kench puts the heft of his immense body behind his attacks and abilities, gaining extra damage based on his bonus health. When activated, Tahm Kench teleports across the map, and he may bring one ally champion with him.
Passive: Basic attacks and damaging abilities deal an additional 0 (20 + 4/5/6% of Tahm Kench's bonus health) magic damage.
Active: Begin to channel for up to 15 seconds. During this time, one ally champion can right click Tahm Kench to join in. Alternatively, reactivate this ability to travel alone. On reactivation or once an ally has opted in, Tahm travels to the target location. Incoming champion damage breaks the channel.'Boy, the world's one river, and I'm its king. Ain't no place I ain't been; ain't no place I can't go again.'

'The whole world's a river, and I'm its king.'
Tahm Kench travels Runeterra's waterways, feeding his insatiable appetite with the misery of the unsuspecting. The singularly charming gourmand savors every moment of his victims' suffering. A deal with Two-Coats may carry you to wherever you wish, but your journey will most assuredly end in the depths of despair.

Offense:9
Sorcery - Tahm K. got a cd problem so we gonna get some extra cd red.
Mental Force & Arcane Mastery - For the extra ap for some dmg
Expose Weakness - Extra dmg on enemy team in teamfights really good.
Defense : 21
Block & Unyielding - Extra tankiness seems like nothing but in long game does alot of reduction.
Swiftness - Less slow = More % of escaping or catching up to the enemy
Veteran Scars & Juggernaut - extra Health always is good
Hardiness & Resistance - Armor & and Magic Ressistance are the main stat's a tank need's
Perseverance & Second Wind - Gonan help alot in the whole game your E will heal you way more than it does and that help's alot as it gives sustain in lane and a nice come back in a teamfight if you get a moment to breath after a flash over a wall or something.
Adaptive Armor - Enemy Team got 4 ad 1 ap ? NO PROBLEM go for armor and this will give you the extra mr you need for that 1 ap champion :) or the oposite .
Legendary Guardian - Armor & and Magic Ressistance are the main stat's a tank need's