My common build (plus jungler item)
good items (Ap and armor/mr items)
You can chance your boots to these
Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
So, this is my first guide, and i hope you like it, or give me some advices what i should change :) I made this because i didn't found any jungler tank Diana build, so I decide to do this. And I say this now, this guide might not be best guide (item set) for those who play a lot Diana, but I would say that this is good for those who have just bought Diana and want to play well with it. Enjoy!
Creeping / Jungling
My basic jungle route is something like this: Krugs -> Razorbeaks -> Wolwes (now use 1 refillable potion) -> Blue buff (use last refillable potion) -> Gromp. After that you might have to recall, but go kill what you want after those. When you reach lvl 6. Start gank, use Q+R+W+E (and if your target is alone and not next to turret, you can cast R second time). Most important thing when playing Diana is that you don't charge too far away, because Diana doesn't have any escape ability (of course you can escape by casting your yor Q to creeps and then go to them with R).
And always buy Stalker's Blade, because slow effect will help you to land Crescent Srtike, and run away if you get hunted
Only thing that i say about summoner spells, do not change Flash or Smite, both are must have things.
Your main task in team is trying to hunt their ADC or AP carry. Other important thing in late game (works only with this build!) is that you are the one who is first one attacking to enemy, and use your shield and soak up dmg, but you also have to keep your eyes open, because if they have low hp champs, you have good abilities to chase them and kill them. Another good to know thing is that it's useful sometimes to cast your Q in random shrub to check if there is enemy waiting perfect time to gank.
So, something about why i pick those items. I started to play Diana as a tank when i relized that it was really hard to play with a "normal" build. My rule of thumb is to pick everything that gives you hitpoints and ability power. Rod of Ages is important to get in early game, because of it passive (full stacks after 10 min) and it's really good item after that. Allso the catalyst the protectors passive is good in the beginning. Rylai's Crystal Scepter, it's also a good choice, because you get 400 hp and 100 AP. Passive is the most useful useful when you use W, then your orbs will slow down enemy and you can let your passive shine. And then your last AP/HP item, Liandry's Torment. That is like a "jack of all trades" with AP champs. You get decent amount HP and AP, but the passive(s) are why this is so special, you get magic penetration AND burn dmg, so i'm sure that you won't waste your money.
Then the other items. I usually buy Ionian boots, because cooldown reduction is good for her (mainly for Crescent Strike). Sorcerer's boots are also a good choice for boots. Then there is one item slot free (plus jungle item) and there you can pick whatever you need, i haven't tried every item what I put on good items, but every item there have good things to Diana. Will of The Ancient (should) be good because of healing effect and AP. Nashor's Tooth is good if you want to trust your auto attack and passive. If you pick Nashor's, then Wit's end could be also bought for insane attack speed. Problem with that combination is that you have to abandon one of your tank items, which is not good. If you decide to buy Nashor's or Wit's, then i also suggest Stalkers blade devourer to you. If you play as a basic tank, then take cinderhulk. Take runeglaive if you think you need more cooldown reduction. Sorcerer's boots are also a good choice for boots. Lich Bane is quite common item when playing Diana, it gives you AP, cooldown reduction, mana, movement speed, and useful passive (when buying Lich bane, try to not use every ability and auto attack then between spells, which can be difficult). And remember to use your common sense, check which champions enemy have and buy your items depending that.