Death (3 sec cast, MP, 3 min CD) – Deal unaspected damage with a potency of 1000. Can only be executed when target’s HP is below 20%.
Additional effect: Instant Death on enemies whose level is equal to or lower than your own.
Additional effect: Fully replenishes Soul Gauge.
Even on a 3m cooldown, that is definitely not a healer skill...

If anything, this could, and probably will, be a BLU skill.