For runes you can choose between having Resolve or Inspiration as your primary page. Resolve as a primary page is better when you believe the enemy has a stronger all-in than you or they have a jungler who ganks a lot like Sejuani or Lee Sin. Since the Resolve tree will overall make you more durable, the runes in it, and Guardian especially, may save your life. However, having Inspiration as a primary page will give you a lot of flexibility as you will be able to switch between different summoner spells throughout the game.

INSPIRATION PAGE
Unsealed Spellbook is your keystone if you opt for the Inspiration page. This keystone lowers the CD of your summoner spells by 25% and allows you to swap out a summoner spell every six minutes. you can alternates between Exhaust, Cleanse and Teleport each game depending on his needs at the time—does the enemy have too much CC and it makes it hard for you to engage? You can just pick up Cleanse rather than have to spend money on QSS or Tenacity items.
In tiers two, three and four you get Biscuit Delivery, Magical Footwear and Approach Velocity. Biscuit Delivery gives you extra sustain to fight off the poke you‘ll inevitably have to deal with.

Magical Footwear gives you a free pair of Slightly Magical Boots at the ten minute mark, which give 10 more movement speed than regular Boots of Speed do and can later be upgraded to tier two boots at a cheaper cost.

Approach Velocity gives you a 10% movement speed boost when running towards an impaired ally, making them more likely to be saved by your Devour, or any enemy you have impaired, making them more likely to be killed by you since you’ll be able to get in their range sooner.

Your secondary page is Resolve.
Font of Life is a great pick-up for Tahm Kench. Impairing the movement of an enemy will mark them, and allies who attack that enemy will be healed. Because Tahm’s main poke and engage tool, his Q Tongue Lash, slows the enemy, he can easily trigger this rune at the start of and during every fight.

The second rune you can pick up is Conditioning, which will grant you 8 armour and magic resistance and increase you resistances by 5% after the ten minute mark of the game. This is just going to contribute to your tankiness in mid game.

RESOLVE PAGE

Your keystone mastery in the Resolve tree is Guardian. When you and your ally are in close range of each other and you take damage, you and your ally will gain a shield and a burst of movement speed. This can help you negate poke and can be taken advantage of in early bot lane skirmishes. During these 2v2s, you can stick to your ADC to trigger the shield and potentially win the fight.

Aside from Font of Life and Conditioning, you also pick up Overgrowth.With this rune, you permanently gain 0.2% maximum health for every 8 monsters or enemy minions that die near you.

You’ll find many valuable runes in the Inspiration tree but the two I recommend above all the others are Approach Velocity and Biscuit Delivery, for the reasons mentioned previously.

SUMMONER SPELLS

Flash: Like most champions, Tahm’s first summoner spell of choice is Flash. It’s useful in every game and will help you chase down enemies, bypass walls and escape from certain doom.

Exhaust: Exhaust is a useful spell throughout the entire duration of the game whereas Ignite will fall off as the game goes along. Exhausting an enemy will slow them and decrease their overall damage by 40%. The damage debuff can either cripple an enemy and give your ADC a huge advantage in fights or it can simply save your ally if they are trying to escape a Zed or Akali.

Ignite: Ignite gives you the necessary oompf needed to secure kills during laning phase. It’s especially useful against champions that heal, since it applies Grievous Wounds which decreases all healing by 40%. Although Ignite falls off as the game goes later, due to enemy durability increasing, against sustain champions like Vladimir and Dr Mundo, Ignite remains quite valuabl

AN ACQUIRED TASTE

Your passive enhances your auto-attacks and abilities in two ways. Firstly, you deal magic damage equal to your maximum health with every auto-attack or damaging ability. Secondly, every auto-attack and damaging ability applies a stack of Acquired Taste to an enemy for up to five seconds. When you apply three stacks of Acquired Taste to an enemy, your Q and W have enhanced capabilities—your Q will stun the enemy and you can use your W to devour them.

TONGUE LASH

Your only ranged ability and thus your only means of poke. With its low cooldown, low mana cost, generous range, and high damage, there’s a lot to like. You want to use this ability relatively often to pressure the enemy ADC and support.

It’s also your only form of CC, so it’s your primary engage tool. If an enemy has three stacks of An Acquired Taste, it’s a one and a half second stun. Otherwise, it’ll slow the enemy for 50-70% which is also potent.

DEVOUR

Devour lets you, well, devour allies and enemies alike! Minions, monsters, champions—Tahm isn’t picky. It’s ideal as a means of rescuing your allies, particularly your ADC; when you Devour an ally, they can’t be hit by any skillshots for four to six seconds. You can rescue them from Thresh hooks, Lux lasers or Miss Fortune’s Bullet Time. It’s also useful when you’re chasing an enemy, as you gain a 30-50% movement speed boost when moving toward an enemy with an ally in your belly

You can spit Devoured minions and monsters at your enemies to deal AoE magic damage, making it an effective poke tool. However, due to the high mana cost, I don’t recommend doing this too often.

Devouring enemy champions is a slightly more complicated matter, as you’ll first need to apply three stacks of your passive to them. This is fairly simple to do, however, using the AA - Q - AA combo which is described a bit more in-depth below!

THICK SKIN

Tahm gains grey health equal to 70-90% of the damage he takes. Once he’s out of combat, he heals for 30-45% of the damage he’s taken. This passive is very helpful in negating poke during laning phase.

Reactivating his E during combat will convert all grey health into a shield, but it rapidly decreases over the next three seconds. You usually want to pop it as a last resort. Ideally you’ll wait until you’ve only got a sliver of health left, as that will make the shield as potent as possible.

ABYSSAL VOYAGE

Tahm’s ultimate is a mini-teleport, with a longer channel, shorter cooldown and the ability to transport an ally alongside you. The best use of this ultimate lies in using it in conjunction with your jungler to gank lanes. The channel can be rather long so it’s best to teleport your ally and yourself either somewhere in the fog of war or in brush. Once you arrive at your destination, hopefully unseen, you’ll have an advantage through flanking and outnumbering an unsuspecting foe.

SKILL ORDER

As with all champions, rank up his ultimate every chance you can—at levels 6, 11 and 16. Aside from this, your first priority is his Q - Tongue Lash. Putting ranks into Q will increase the damage it deals and the potency of its slow. Since it’s your only ranged spell, and thus your only means of poke, it’s crucial that you max it out during laning phase to make yourself more of a nuisance.

After Q you should max Devour. This will lower its cooldown, therefore allowing you to save your allies more often. This is important during the mid game when any of your allies getting caught may result in a lost teamfight or objective.

Finally you have Thick Skin which you max last. It’s a useful skill, but it doesn’t improve much when you put extra points into it. The healing increases but in general the shield is more useful so there’s no need to max it up just for the healing.

DEVOUR COMBO AA - Q - AA - W

This is the most basic and common combo and it’s very useful during laning phase. You need to apply three stacks of your passive onto a target before you can devour them. As your Q is an auto-attack reset, the fastest way to apply three stacks is to get into melee range of an enemy, AA them once then quickly Q and AA again.

One thing to keep in mind is that you want to have your enemy in your belly for as long as possible when you devour them— this allows you take them out further from their safety zone and gives your Q more time to come off cooldown.

LONG RANGE DEVOUR Q - W

When your Q contacts a minion or small monster, you can immediately activate your W to eat them. This combo costs only 50 mana instead of 140, which makes for some cheap harass in lane. You can also use it to secure canon minions in a losing lane, by eating and spitting it out closer to your ADC. Or you can just use it to annoy the enemy jungler by taking away his raptor, golem or scuttle crab!

STUN COMBO

It is a bit difficult to apply a stun using Tahm’s Q. You will need to first somehow apply three stacks of your passive before using your Q. This means you can’t rely on the above combo. Instead, it’s easiest if your ally is able to CC the enemy somehow and allow you to AA them three times. If it’s an extended fight, you can Q to engage the fight then Q again later when you have enough stacks.

Usually you’ll want to help your ADC soft push the first wave by sporadically attacking enemy minions, being careful not to mess up a last-hit for your ADC. This will mean that you and your ally will kill the enemy wave before they kill yours. In the second wave, only three melee minions need to die before you and your ally hit level two. Ideally, you’ll have a level advantage now and can engage a fight.

The number one rule when fighting is to auto-attack a lot. Firstly, you’ll be applying stacks of An Acquired Taste, allowing you to secure a Devour or a stun with your Tongue Lash. Secondly, your auto-attacks deal decent damage because of your base AD and bonus magic damage from your passive.

Tahm doesn’t get much stronger after level 6 because your ultimate is primarily used to gank, and it doesn’t do any damage or contribute to skirmishes in any meaningful way. However, you do undergo a powerspike at level 5 because at this point your Q and autos are very powerful and the enemy is still quite squishy.

Another tip is to play around the brush area. This will put more pressure on the enemy who will be vary of you, not knowing where you are, and be forced to play safe. Being in the bush will also makes easier for you to avoid poke.

It’s important to mention roaming, since Tahm is one-of-a-kind here. As previously mentioned, Tahm can pull off a surprise two-man gank in any lane by teleporting into brush or fog and flanking the enemy. The real question is, when’s a good time to gank and when’s a bad time?

GOOD TIMES TO GANK:

1. Whenever your jungler is ready to go gank as well. You can teleport the two of you to a chosen lane and wreak havoc.

2. When you’re at the enemy tower bot lane. The enemy is forced to play safe and CS under tower, meaning you’re pretty much free to go about your business.

3. The enemy mid laner is at your ally’s tower—AKA he’s over-extending and far away from his own turret.

4. You just recalled and are about to go back bot lane. This is a good time to roam mid or top (with your ultimate) as the enemy bot lane won’t notice that you’re missing—they will assume you are still in base or on your way.

It can also be helpful for your mid laner to ward for him or cover him while he pushes the lane, not every roam needs to involve getting kills!

BAD TIMES TO GANK:

1. Your ADC and you are stuck at your turret. This means that if you leave, your ADC will struggle to CS and possibly suffer a tower dive.

2. Your mid laner is at the enemy tower. This means it’s impossible to flank the enemy mid laner and the only way you can get to him is by diving. If it’s just the two of you, that’s almost always a bad idea.

Tahm is not a strong initiator because he only has one ranged ability with which he can CC enemies, but it is possible for you to spark teamfights with your ultimate if you can manage to surprise and flank the enemy with another ally.

Your primary job instead is to protect your ADC, as both his support and as a tank. Be ready to Devour them at any point, and keep your Q handy to CC and peel enemies off your ADC. Sometimes a Devour is not enough though. For exempel your Caitlyn is in truble and in order to save Caitlyn you have to both Devour and then Flash as well so as to get her out of range of both Sejuani and Rakan. The key to good teamfighting is be aware of all the enemies at all times and to be able to predict what they might do.
Other times it’s better not to Devour your ally at all