Ryze, the Rogue Mage, has great damage output based off of his mana. Building purely as a mana tank is a viable and recommended build. I always go mid as Ryze because his casting range makes him a great harass against most champs. The reason I've made this guide is because I've seen a lot of guides going 9/0/21 and not getting the Strength of the Spirit mastery. While Mastermind is nice it is not as good as having the +10% cdr and 1% mana as hp5 from the masteries at 8/0/22.

Always buy Sapphire Crystal as first item, it will increase your damage by 16 on your 'Q' as well as with this build give you 643 mana at level 1. That with Strength of the Spirit gives you an extra 6.43 hp5.

With this build I suggest getting the mana pot purely because you can easily be in lane until level 5 or 6 without going back. Every level with these runes will make your mana go up by 102 thus increasing damage by 8.16 on 'Q' and hp5 by 1.02 each level. This will allow you to lane longer and possibly pick up a few kills. I usually get 2 kills before going back if they are careless but at least 1 is the norm.

Ryze's passive reduces CD of his spells 1 second each time a spell is cast. This is his bread and butter allowing him to continue to cast and harass. Max Cooldown of his spells yield a 2.1s CD for his Q and 8.4 for both W and E. I always lead off with Q then W to keep them in place if I need to and then E which lowers magic resist. At this point your Q will be off cooldown and you can recast it. If you're above level 6 it is at this point I will activate his ulti which will allow you to cast Q again within 1 second and W and E should both be coming off cooldown allowing for another set of W, E, Q. At this point if your target than you need to stop focusing their tank.

At level 6 you get a mana bonus from Ryze's ulti which is not much, but it definitely helps. Tear of the Goddess should be finished before boots but by level 6 you should have enough gold for both. After that you should get Catalyst the Protector giving you more health and allows you to stay in lane even longer. Rod of Ages should be finished asap along with Merc Treads. I go Mercs because of the tenacity and MR. Even if you're laning against an AD champ the tenacity will likely come in handy especially if ganked. Ryze has no escape so being able to run out of stuns and taunts is a must. I then get a Manamune, I am usually level 12-14 by this point and have 3400 mana, this will yield a nice amount of AD most of the time it is more than most AD champs have thus giving you a better farm and also something to do while your spells are on cooldown. Ryze's cooldowns are relatively short and at level 9 you will have 20% CDR, but at this point you will still be auto attacking from time to time. So we are about 20 minutes in and the AD champs are going to start getting some of their core damage items. Time for the Frozen Heart. Glacial shroud is a great item for a little over 1500 gold you get a nice amount of mana and 45 armor with 15% cdr. This will give you 35% and more tanking ability in team fights if they focus you then your teammates will be grateful you do not die in 1 second flat. If they dont focus you then you can clean up pretty will while getting nice AOE damage from his ult.

To go along with tanking; after Frozen Heart you get Banshees Veil, another Catalyst item which means it gives more Health and Mana. Banshees also gives MR and blocks one enemey spell every 45 secs. This item is great for the price and will bring you up to a decent MR ~110 with the boots. At this point you should be around 5k mana and 3.1k health so you are doing nicely with damage and sustainability. This means more sustainability is the next move. I get Force of Nature which with Strength of the Spirit yields an hp5 of about 111. As Garen users know 22 heath regen per second is a nice thing to have in dire situations. Plus having 180 Armor and 156 MR doesnt hurt either. If the game has lasted this long your teammates are feeding or aren't working together at all, but it does happen. I will usually get the 3 elixirs at this point.

You're sitting on 3k gold and have no spots left in inventory, time to sell the boots. You don't want to lose all that movement speed and magic resist for purely more mana so you get a Lich's Bane stacked with the Force of Nature your movement should be about 365-370 with masteries which is enough to get your around. At this point in the game you can solo baron if you feel so inclined to do so. I've done it a few times it shocks people when champs like Ryze do it. So enough rambling I just wanted to give my $.02 on Ryze, use Strength of the Spirit you will tank me later when you live with 31 health and realize its because of your regen.

306AD
280AP
180Armor
190Magic Resist
3149 Health
5763 Mana
112hp5
40% CDR
Largest Crit 913(OMFG did Ryze just crit me?)

Give this build a try, I've spent hours playing just Ryze to perfect the order and dominate with it.