Overview
Basic Mechanics
What is Runic Ward?
Runic Ward acts as a hit pool that can absorb Damage, which is below your Life in the default order of operations for taking Damage. When your Life reaches 1, any Runic Ward will begin to be lost through Damage taken. If your Runic Ward reaches 0 and the last point of Damage is dealt to your remaining 1 Life, you die.
Runic Ward is visualised as a Runic symbol on top of the Life globe.

Runic Ward visualised
Note: total Runic Ward is also added to your starting Resolve upon entering the Trial of the Sekhemas.
Recovering Runic Ward
Runic Ward is recovered over time by default via a base Regeneration which is independent of your Life.
Runic Ward has a base Regeneration rate of 5% per second, which can be scaled via modifiers to 'Runic Ward Regeneration Rate' or 'Runic Ward Recovery Rate', such as the use of a
Greater Charging Rune. You can also use others methods of Runic Ward recovery, for example
Warding Rune of Nourishment will apply some of your Life Flask recovery to Runic Ward as well.
Obtaining Runic Ward
Runic Ward is primarily sourced from gear pieces such as Body Armours, Gloves, Boots, Helmets and Shields after they've been modified using the Runeforging bench. Items at Level 55 or below have Runic Ward added to their existing stats, but higher Level items will trade some of their basic Defences such as Armour, Evasion or Energy Shield, for a higher amount of Runic Ward. Once an item has been modified by the Runeforging bench, it will have the 'Runeforged' prefix name, indicating that it cannot be modified further by the same bench.

At low levels, adding Runic Ward to gear is purely an upside
Some Unique items will also have special interactions with the Runeforging bench, such as
The Brass Dome having its Armour fully replaced by a large amount of Runic Ward instead.

Runeforging a Brass Dome will fully replace its Armour with Runic Ward
Scaling Runic Ward
There are more than 15 Runes introduced in the Return of the Ancients update that can scale the amount of Runic Ward you can obtain, or modify its mechanics directly.

The Ward Rune simply adds flat Runic Ward to the socketed Armour item

You can improve the base Regeneration of Runic Ward
These Runes and more can be found as rewards by interacting with the new Runes of Aldur league mechanic.
Runic Skills
Like other resources, Runic Ward can be used for other purposes, such as the use of Runic Skills which naturally cost Runic Ward instead of Mana or Life to use. For this purpose, Runic Ward has a base Regeneration effect so that it can recover over time after being spent to use Skills, or after absorbing Damage.