Heartpiercer vs Gravechill Killer

Overall comparison

HERO	Fraction	Element	Type	Rarity	Aura
Heartpiercer	Dark Elves	Force	Attack	Uncommon	-
Gravechill Killer	Undead Hordes	Magic	Attack	Rare	-

HERO	LVL	STARS	HP	ATK	DEF	SPD	C.RATE	C.DMG	RESIST	ACC
Heartpiercer	60	6	12555	1057	859	89	15	50	30	0
Gravechill Killer	60	6	13545 +990	1233 +176	892 +33	96 +7	15	50	30	10 +10

Heartpiercer	Perforate Formula: 4.6*ATK Attacks 1 enemy.	Sight In Formula: 7.6*ATK Attacks 1 enemy. If the hit is critical, places a 25% [Increase ATK] buff on this Champion for 2 turns. Cooldown: 4 Increase ATK 25%	-
Gravechill Killer	Freezing Toxin Formula: 3.9*ATK Attacks 1 enemy. Has a 40% chance of placing a 5% [Poison] debuff for 1 turn. Poison 5%	Blood Chill Formula: 6.8*ATK Attacks 1 enemy. Has a 75% chance of placing a 30% [Decrease DEF] debuff for 2 turns. Has a 75% chance of placing a 60% [Decrease DEF] debuff instead if the target is under a [Poison] debuff. Cooldown: 4 Decrease DEF 60% Decrease DEF 30%	Icy Veins Formula: 2.65*ATK Attacks 1 enemy 2 times.Each hit places a 2.5% [Poison] debuff for 2 turns. Places a 5% [Poison] debuff instead if the target is under a [Poison Sensitivity] debuff. Cooldown: 5 Poison 2.5% Poison 5%