Warrior's Blessing - Good for early sustain and mitigation.

Gladiator's Shield - Core sustain item, works better with more physicals on the enemy team. Also gives 10% CDR.

Reinforced Greaves - Tank boots, for more mitigation.

Blackthorn Hammer - Health, Mana, Mana Regen, and power all in one item. Also gives 10% CDR (when above 25% mana)

Soul Eater - For more sustain on abilities, also adds some power to your abilities so you get more healing from it. Also gives 10% CDR.

Mail of Renewal - I build this item last because it has 400 HP, but you can alternatively get Stone of Gaia if they have a lot of ways to proc its passive. This item is more effective in team fights as you can regenerate even more health with assists. And it maxes out your CDR with this build.

If you grabbed all of these items, you'll have 40% CDR, and a hell of a lot of sustain. It should be much easier to survive teamfights with very minimal damage.

Relics are free choice but in general you'll want at least beads to shrug off any CC they throw at you to stop you from sustaining.

You'll want a lot of health to increase the amount of healing Gladiator Shield gives you, and a good amount of power to increase the amount of healing Soul Eater gives you.

Example: If you have 2000 HP, every proc of Gladiator's Shield will heal you for 50 HP. If you have 2500, you'll heal 63, 3000, you'll heal 75. And you can proc it up to 5 times per ability (not counting his Uppercut and Excalibur's Wrath.).

However, Soul Eater is not limited to one hit per god, so it's an extendable sustain for your Bladestorm.

You can sell Warrior's Blessing for a variety of items depending on the situation. If you need more power, you can grab Transcendence or Bloodforge, even Shifter's Shield, or if you just aren't mitigating enough damage, then Mantle of Discord, Spirit Robe, or Hide of the Urchin might be appealing. This build is flexible in that the only core items are the sustain items. The blessing slot and the last item slot are interchangeable with whatever you need.