Oh one more thing, Deadliness outscales Havoc both early-game and late-game. So you should take points out of Havoc and put them into deadliness.

Also, since you are building 2 crit items on him (atma's and youmuu's), you should probably take Lethality as well.

Good point on fratmas. I've always preferred Warmogs simply for the
extra survivability over Frozen Mallet. I think the fact that Warmogs is 200 g cheaper and offers 600 more health overshadows the + 10 AD and permaslow. But you're right in that building Mallet helps out much more in the laning phase. It's definitely a viable option.

I take Last Whisper over Black Cleaver when the focus target has over 150 Armor simply because at that point, they have so much armor that even with all your base reductions, 40 % of their leftover armor is still a significant chunk. Also, Last Whisper is applied on your ultimate (assuming you use it right away like you should) while Black Cleaver isn't.

Excellent guide, I have some suggestions though:

frozen mallet over warmog's: I think FM is better than warmog's for a number of reasons:

1. atmog's vs. fratma's: when paired with atma's, warmog's gives 19.05 AD from atma's. Frozen Mallet gives 30.5 AD (20 base + 10.5 from atma's). So FM gives more AD.

2. frozen mallet gives slow, this ensures that after you E in, you can stick to your target for a guaranteed kill. Since Xin plays like an assasin, you want the extra cc to ensure the kill.

3. probably most importantly, phage is amazing for xin during laning phase. Statistically you are guaranteed a phage proc whenever you do an E-AA-Q combo.

Also I wouldn't recommend last whisper under any circumstances. You already have multiple sources of armor shred, and %-penetration gets applied very last. If you want more armor shred late-game, get black cleaver, it synergizes way better with flat armor pen.

Ty was thinking about this too.

He means Three Talon Strike.

Sry but i am new and don't get it, what means TTS?
AA is Autoattack right?.
BTW ty for this great guide now i am going higher :D

I already explain the move command + TTS combo in the Teemo Lane matchups section, and I'll talk about the E splash damage under the skill description.

It should be noted that you can extend the range of your E by charging a nearby minion if the enemy champ chooses to play it safe. I've gotten countless kills on vlad/teemo by charging a ranged minion that they're hiding behind, only for the aoe slow/damage to still hit them so I can continue my combo. Most players will resort to standing back behind their ranged minions once you've killed them once or twice, so this is a valuable tactic to know and utilize to continue your snowball

Another tip is when you charge in and start your Q+W combo to walk with the enemy in between Q-autos so that you can position yourself in such a way to get 1-3 free autos after the knockup. This is particularly effective against vlad and teemo because you can wait out the teemo blind or vlad pool as they try to run away/kite you and continue your combo to easily win the trade and perhaps even score a kill if they were low hp to begin with.

With these two tactics teemo is much less of a counter for xin especially if he starts Q. You could easily score FB after lvl 2 utilizing these methods.

E + AA is pretty minimal harass. You need to pop Q to do any significant damage, and if your Q is only + 15 Physical Damage, it's not much of a threat. That Irelia will just stun you and wither away at you with her 75 + true damage steroid. The slow is good, but having your Q CD go down so you can knockup twice in one fight/engage/chase is even better. Maxing Q does more damage because of armor pen as well.

About Q vs E dialog. IMO E is better in utility. E + AA + disengage is a great harass, and no melee without jumps can catch you out. Lower Cd on e can help the escape in sticky situation. And the slow is good when you're recieving ganks.