The Eye of Blood

The Eye of Blood is a Hardmode boss available after defeating all three Mechanical Bosses. It is one of the six Eyes of Old.

Summoning
The Eye of Blood can be summoned after using the Bloody Pupil in the Crimson Biome. Attempting to summon the boss pre-Hardmode by using a second world will instead produce a message saying "'The Eyes of Old deem you unworthy.'"

Fight
Eye of Blood Health: 70,000 | 120,000

Phase 1: Body (Melee): 60 | 90

Body (Defense): 35 | 45

Blood Droplets (Melee): 45 | 80

Debuff Duration (Bloodied Armor): 12 seconds

Phase 2: Body (Melee): 70 | 110

Body (Defense): 30 | 50

Blood Droplets (Melee): 55 | 100

Crimson Worms (Melee): 60 | 80

Crimson Worms Health: 1,000 | 2,000

Phase 3: Body (Melee): 60 | 100

Body (Defense): 20 | 40

Blood Droplets: 50 | 95

Crimson Worms: (Melee): 60 | 80

Crimson Worms Health: 1,000 | 2,000

Mini EoB (Melee): 60 | 90

Mini EoB (Ranged): 40 | 80

Any attack by the Eye of Blood will have 20% chance to inflict the Bleeding debuff. This debuff ignores debuff resisting items.

The EoB will initially rise quickly out of the ground, heading straight toward the player. This initial attack does 160 damage. The boss will then try to remain above the player dripping Blood Droplets at a moderate pace and summoning Wandering Eyes. The Blood Droplets remain on the ground for five seconds and inflict the Bloodied Armor debuff. After seven seconds the EoB will make two dashes at slow speed and then a third rapid dash that covers twice the distance. The EoB will repeat the cycle until it enters it's second phase.

When the boss reaches 70% | 75% Hp it will enter its second phase. During the second phase the boss will start to rapidly dash at the player. The boss will also continue to drip blood droplets from its now open mouth. The EoB will also start to cough out crimson worms which will follow the player with the worm ai.

After the boss reaches 40% | 50% Hp the boss will enter its third phase. During the third and final phase the boss will stretch it's jaw and cough out four mini EoB connected with a long vein. The vein has a maximum distance of 30 feet away from the boss. The mini EoB's will begin to shoot Blood Droplets at high velocity at the player, the speed in which they attack will increase. The boss wilk still cough out Crimson worms at a much slower pace and will attempt to remain a moderate distance away from the player. At 25%, 20%, 15%, and 10% health one of the mini EoB's will break off and dash at the player. They are invincible and only die after the boss has been defeated.

Aftermath
The speed of the spread of crimson will be halved.

If this is the first Eye of Old defeated: "'You feel an ancient evil gaze upon you'"

If this is the second or third Eye of Old defeated: "'You feel the gaze grow stronger'"

If this is the final Eye of Old defeated. "'The Eye of Reality is rushing towards you'"

Drops
1 Bloody key 100%

5-10 Souls of Blood 100%

1 Red Cornea 50%

1 Bloody Eye Staff 20%

1 Artery Ripper 20%

1 Eye of Blood trophy 10%

1 Treasure Bag (Eye of Blood) 100%

Tips
During the first phase speed boosting accessories like hermes boots are highly recommended to avoid the Blood Droplets.

During the second phase speed accessories are still helpful to avoid the rapid dashing.

Trivia
Leaving the crimson while fighting the boss will cause it to become invincible and gain a massive speed boost until the player returns to the crimson.