With Guan in the early, you won't want to waste time on getting Gladiator's Shield online. It's a vital item for him and the stats it gives in the early game while only costing 1700 gold is an excellent pay off! Health & Multi potion are great to pick up so that you can stay a little longer.

Picking up Shell is one of the best relics you can get, if the enemy team builds anti-heal you won't have to worry about it being countered like Meditation would. In addition when you upgrade it later on, you and your teammates will get 2 stacks of block, which can help in some situations.

Level 12! Now you can pick up that second relic that gets over looked and you now have the majority of the build down. It is important to note that you go into Genji's Guard instead of Breastplate of Valor, Genji's costs less, but only by 100. However since you got Gladiator's Shield online in the earlier stages you'll be wanting magical protections at this point and proc you get from Genji's makes a big difference! From there go right into Breastplate of Valor for the extra CD along with physical protection. After that start on Warded Shield which you'll eventually build into a Runic Shield.

Now you might be looking at Bracer of Undoing and wondering why that's there, because it can be countered by anti-heal. Right you are, but hear me out. See Bracer of Undoing plays a big part in this build because even if you are being slammed by anti-heal you still get the cooldown off of it! With Guan's kit you want to keep spamming that heal every chance you get. His heal with max passive stacks reduces the cooldown of all abilities, so yes even your ultimate which means more usage of horsey!

All finished you are now a CD monster! You'll want to finish the build off with Runic Shield, since Mages are pesky so reducing their magical power will help out oh and the magical protections are also nice. Now unfortunately the downside to this build is you aren't a speedy boy nor are you going to pick up many kills, you're really just going to be spamming heal and ultimate so for the last item you'll want to buy something nice for yourself. Mail of Renewal is the item I recommend for your last slot, you are capped at CD at this point, but that doesn't mean the HP and gaining back 15% of your max Health and Mana whenever you get a kill or assist won't come in handy! In truth the last slot you can really put whatever you want in, Mantle of Discord or Void Shield are also great items if you don't prefer to use Mail of Renewal. Magi's Cloak too for a free purification if you keep getting caught in cc.