Radiant Protector's Vow

radiant

Combat Start: Gain 40 Mana.

At 40% Health, gain 30 Mana and a Shield equal to 50% max Health

Source

Shield

A Shield is temporary HP that sits on top of a unit's real Health.
Mana

Mana is the unit-level resource that gates ability casts.
Mana Regen

Mana Regen is a stat that trickles Mana into a unit every second on its own.
Armor

Armor is the physical-defense stat that reduces incoming Attack Damage (AD) damage.
Magic Resist

Magic Resist is the magic-defense stat that reduces incoming Ability Power (AP) damage.
Combat Start

Combat Start is a trigger that fires once, as the round's fighting begins.