What "as a vampire" means?

Some allies can use disciplines or do things "as a vampire", reanimated corpse being a example

Name: Reanimated Corpse
[LoB:C, HttB:PSam3]
Cardtype: Ally
Cost: X blood
Discipline: Thanatosis
Zombie with 2 life. 2 strength, 2 bleed.
[thn] Put X pathos counters on this corpse when it enters play. During your unlock phase, burn 1 pathos counter. Remove the corpse from the game if it has no pathos counters. The corpse can play combat cards that require basic Fortitude [for] as a vampire.
[THN] As above, but put 2 additional pathos counters on the corpse.
Artist: Roel Wielinga

Some people are saying that this allie can play life as blood to pay for some fortitude cards, i disagree, "as a vampire" allow to use one resource (life) as another (blood) ? I think that can't, can someone clarify this to me?