I've been facing a few darius lately and want to know what I'm supposed to do against him after laning phase. I can crush him in lane hard but get completely stomped once he has one or two items and comes charging at me. Also I play panth a lot so it be nice if anybody else who plays him can give some tips.
Best thing to do against Darius? Uninstall and pray to Urf for Ritos forgiveness
Run. Run. Run. Run. And, bribe him, if that doesn't work, let him have a tower, butter him up, AND THEN 4 MAN GANK THAT SHIT, CC HELL HIM
in champ select, you ban him.
then you don't have to deal with him.
jokes aside, like any other kiteable champ, you have to bait out his abilities and respect his zone of control. if he misses Q or apprehend that is an opportunity to go in on him. if he uses Q to push a wave, an opportunity, etc. granted, Q has a short cooldown so its not a big opportunity.
I've found that the only way to beat a darius is to do quick short trades with him. because if you try to go all in you HAVE to kill him. if you don't, he gets the 5 stacks, goes into noxian might and you are pretty much dead. its all about wittling him down and denying the Q heal. if you can't do that you can't beat him.
that said as well, not many champs can truly 1 v 1 him once he gets items against you anyway. even in LCS, marin still got solo'd by a darius twice even though he was well ahead in the match up. Darius passive is quite strong and honestly broken right now. it is truly better to ban him and wait for nerfs imo.
i always beat a darius with olaf.... but tbh hes not the invincible tank that people would think he is. you just gotta poke him down out of his engagement range and coordinate with your jungle or make calculated risks
My best success against Darius is to play Nasus and farm under tower, giving up minions if necessary. I usually lose tower as well but about 3 minutes later I have farmed q enough to outscale him and beat him at duels and take his tower.
honestly, that's probably just how it's going to be. you can poke him down in lane fairly easily, because being kited is his weakness. i don't think there is a good way to fight him melee as pantheon. just cc him and hope your squishes can kite / dodge his q heals.
I won't list any champions that already have been listed from the people above me so here.
If you're any decent at 
he is one of darius's hardest counters right now. If Darius ever uses his q you just q on top of him and he misses cause of the edge hitbox nerfs and then you just e making him unable to stack anything after that he'll probably be at half hp and zoned from the minion wave rinse & repeat just remember to ward.
Otherwise 
does incredibly well against him if you stick really close to him when ulting he'll never get an edged q and won't kite you with slows cause of CC immunity. Olaf is just generally a dominate champion against darius most of the game.
Two basic ways to play against Darius.
. When he tries to engage, you just walk back and throw your dart/timewinder/cleaver for free damage. This is the easier/safer strat.
to get right next to him and dodge the main hitbox of the dmg. You need to be careful with this strat, because if you screw up you're going to get dunked!With , I would recommend a mix of the two. Stay back poking with your Q. When he gets low enough, then try to W in and take him out (use W to dodge Darius's Q dmg). Haven't tried this, but you may want to run some kind of mana regen item since your Q spam can leave you OOM pretty fast. Maybe 
or 
. My $0.02.
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Really though, he is pretty dominant in top lane right now, but I am sure there are some counter play guides/youtube videos.
