The Blood Vial first appeared in Blood Omen after Kain became a Vampire. The Vial; which represented Kain's health; was a red gauge to the left of the status box. The Blood Vial would drain over time and as Kain took damage, but could be refilled by drinking the Blood of red-blooded enemies, NPC's and Chained humans (including the use of Blood Gout, Blood Shower and the Flesh Armor), picking up blood beakers or using Blood fountains, the Sanctuary Spell, or the Heart of Darkness relic. When Kain 'fed' in this manner, the eyes of the skull above the blood vial glowed red and the skull 'spat' blood into the blood vial; once the blood vial was filled, it would 'overspill' and blood would be wasted, but the Blood Vial could be extended by collecting Blood Vial items. If Kain's Blood Vial ran out he would automatically use a Heart of Darkness relic; If Kain did not possess one, he would 'die' crumbling to dust[Blood Omen].
The Vial returned with minor cosmetic differences in Blood Omen 2's HUD (with the HUD appearing to the top-left of the screen). As before the blood in the vial represented Kain's health and would be drained over time and filled by feeding from enemies, NPC's and Chained humans. A new system of Lore controlled progressive extensions to the Blood Vial as Kain drank Blood. As before once Kain's Blood Vial was drained completely , Kain would 'die' crumbling to dust. Unlike Blood Omen however, the natural draining of the Blood gauge over time could not kill Kain, only damage could[Blood Omen 2].
The Blood Vial returned in Legacy of Kain: Defiance, again with minor cosmetic changes, taking on a globe feature at the bottom of the on-screen display (now in the bottom left). As in previous appearances the bar would be depleted over time and with damage, (instead of 'dying' a drained health meter would cause Kain to flee using Bat Flight). The Bar could be refilled by drinking the Blood of enemies or Chained humans, or by drinking from blood basins[Defiance] and could be extended by collecting Health talismans. In Defiance, Kain could be killed by the natural depletion of the Blood Vial over time[Defiance].
- In Blood Omen, Kain had to be careful what blood he consumed; though red blood would fill his blood vial, black blood would drain it and green blood would poison Kain, continually draining his blood vial[Blood Omen].
- Blood Omen 2 presents the only time in the series when Kain refills his blood vial by feeding from corpses[Blood Omen 2]. Most of the games use a waver state ensuring Kain feeds from 'stunned' enemies[Blood Omen][Defiance].
- ↑ "Blood Vial: Indicates Kain's current health" Silicon Knights/Crystal Dynamics. Blood Omen:Legacy of Kain manual. pg16(Eidos Interactive). (1996) Download.
- ↑ On-Screen Screams: "Kain's life blood. The size of the vial is raised by finding Blood Vial power-ups. It is filled by grabbing Blood Beakers or draining victims." Prima Games / Ian Osborne. Blood Omen: Legacy of Kain: Official Game Secrets (1996). Page 2.ISBN 0-7615-0363-3
- ↑ Blood Sucking: Prima Games / Ian Osborne. Blood Omen: Legacy of Kain: Official Game Secrets (1996). Page 13.ISBN 0-7615-0363-3
- ↑ "Blood Meter/Life Force: This is the leftmost vial. As Kain takes damage, his blood decreases and conversely, as Kain drinks blood, his life force increases. When the blood meter is empty, Kain dies and restarts at the last activated checkpoint. Please note that blood isconstantly being used and the blood meter gradually decreases over time" Crystal Dynamics. Legacy of Kain: Blood Omen 2 manual. pg17 (Eidos Interactive). (2002) Download.
- ↑ "Heads-Up Display (aka HUD)The red vertical meter on the left is your Blood Bar. During the game, it will slowly run dry. If it becomes entirely depleted, you will die. To refill it, you must suck blood from the bodies of your enemies" Prima Games. Prima's Official Strategy Guide to Legacy of Kain: Blood Omen 2(2002). Page 2. ISBN 0-7615-3774-0
- ↑ "Health Gauge: - Holds Kain's health. This guage is a globe of blood, which is depleted when Kain is wounded or as his hunger grows. The guage is filled by drinking enemies' blood and drains as Kain searches for more victims. You can increase your health capacity by finding Health Talismans, allowing Kain to build up a greater supply of health to meet increasing game dangers. To drink blood, press and hold the feed button on a vulnerable enemy. The longer you hold down the button, the more blood you'll drink." Crystal Dynamics. Legacy of Kain: Defiance manual. pg12. (Eidos Interactive). (November 11, 2003) Download.